Osama the Hero by Dennis Kelly, directed by Syd Brisbane. Designed by Kate Davis, sound design Tommy Spender, lighting design by Nik Pajanti. With Jessie Beck, Kevin Hopkins, Hannah Norris, Xavier Samuel and Thomas Wright. The Rabble @ La Mama Courthouse Theatre untilJuly 7.

Ying Tong: A Walk with the Goons by Roy Smiles, directed by Richard Cottrell. Set and costume design Michael Scott-Mitchell, lighting design Damien Cooper, sound effects by Paul Charlier, sound design by Jeremy Silver. With Jonathan Biggins, Tony Harvey, David James and Geoff Kelso. Sydney Theatre Company presented by the Melbourne Theatre Company @ the Arts Centre Playhouse until July 28.

Circus Oz: Under the Big Top. Various artists. Birrarung Marr Park (between Federation Square & Batman) until July 15.

Little Alison felt rather strange last week. I emerged from a tunnel more than half a million words long to find an alien world in which the force of gravity had decreased by around 75 per cent. Birds tootled merrily in the trees, the clouds were the colours of ice-cream and dogs bounced along the street like helium balloons. I was buzzing around Melbourne like a stoned hippy.

This, thought I, is what it's like not to be a writer. Whatever was I thinking? But life, being stern and unforgiving, reminded me that there's really not anything else I can do with myself (and if sufficiently threatened, I'll admit I quite like it, really); so it's back to the word-forge for me. Especially since I've seen three shows since last Thursday, and had better earn my tickets. I realise I'm cheating slightly by doing an all-in-one, but I fear that happy word-free daze was rather seductive, and I've been a little hoppity about writing anything.

On Thursday, I went with immense curiosity to the opening of The Rabble's production of Dennis Kelly's Osama The Hero. The Rabble is a Sydney-based collaboration between Syd Brisbane, Kate Davis and Emma Valente. I've been aware of these artists for some time, but this is the first Rabble production I've seen. It confirms my suspicion that this is a company to watch.

They're an interesting bunch, to say the least, and they're not exactly short on ambition. Davis and Valente are young artists who were previously based in Melbourne, where they founded a company called Self-Saucing Pudding. Their work was seen here last year, when they produced a fascinating take on revenge tragedy for Hoist Theatre at Theatreworks. Most recently, Kate Davis directed Corvus, by the young Melbourne writer Jasmine Chan, for The Rabble at Carriageworks in Sydney. Syd Brisbane has been around a little longer; he was originally based in Adelaide, acting with companies like the Red Shed and Brink Productions and, after Brink's co-production of the world premiere of Howard Barker's Ecstatic Bible at the 2000 Adelaide Festival, with Barker's company The Wrestling School in the UK.

Osama The Hero is a remount of a production that premiered in Sydney last year. Sydney in fact seems to be making the running on Dennis Kelly, an intriguing British writer who made big waves in 2003 with his nightmarishly surreal play Debris, which toured here last year from Sydney as part of the Fringe Festival. It's easy to see why he attracts attention: Kelly is a writer whose work combines a gift for poetic with often brutal realism, out of the school of Sarah Kane, David Harrower or Anthony Neilson. Like these playwrights, his work emerges from the spiritual desolations and alienations of contemporary Britain: while Debris concerned itself with violent family dysfunction, Osama The Hero explores the ethics of social paranoia in a time of terror.

Written in a series of fragmented monologues and dialogues, the play circles around the naive misfit Gary (Xavier Samuel), who lives on an estate where someone is blowing up rubbish bins and garages. When he is asked to present a paper at school on a contemporary hero, he comes up with Osama Bin Laden. He argues that Bin Laden - an ascetic who has fought for his beliefs, who turned away from a massive family fortune to fight the Russians in Afghanistan - is, to those who admire him, the equivalent of Churchill to the British. And he asks why it's considered heroic to kill thousands of civilians in one circumstance (Dresden, for example) and not in another (such as the events of September 11).

His paper causes a scandal, and attracts the attention of the siblings Louise (Hannah Norris) and Francis (Thomas Wright), both the products of a particularly brutal father. Francis is a speed-burned paranoiac, whose free-floating aggression is at first directed towards Mark (Kevin Hopkins), whom he believes is a paedophile. But when he hears about Gary's paper, he is convinced the boy is a terrorist and must be responsible for the explosions on the estate. In a gruelling scene, he and Louise turn vigilante: they capture Gary, tie him to a chair and torture him.

This sink-estate brutality is intercut with visions of middle-class aspiration and failure. The couple Mark and Mandy (Jessie Beck) exemplify a Posh-and-Becks aspirational fantasy: material wealth and comfort, the sheen of a "successful" marriage with the obligatory cute child. But it swiftly becomes clear that they are as emotionally impoverished as their neighbours, as spiritually alienated, as lost and as brutal. The play closes with three intercut monologues which open up the desolate loneliness, the desperate desire for simple human kindness, that in different ways drive all Kelly's characters, and which deliver a indictment, at once damning and compassionate, of an alienated, grossly materialistic society.

Osama The Hero is not as successful a play as Debris; for one thing, while it never falls into the trap of moral proselytising, it sometimes totters along the edge of it. But more specifically, I couldn't escape the feeling that this play's cruelties are so particular to Blair's Britain - to its sink estates, its class system and tacky television celebrity, even its urban landscape - that transferring it to an Australian context makes it lose much of its power. I'm not quite sure why this is so: after all, it's entirely possible to watch plays from 19th century Russia or 16th century Spain and not to feel at all alienated by their context; but I suspect that, except in the moments when Kelly touches a true humane complexity, his vision is limited by a very specific anger. This play was, after all, written in response to the UK's invasion of Iraq in 2003.

All the same, it's worth noting that Kelly's analysis of the crudities of mob justice is rather chillingly replicated on one of our very own right wing blogs. The mere title of the play was enough to bring out the slavering wingnuts, who - like Kelly's vigilantes - never permit mere facts to get in the way of a good bigotry. (I'm not giving a direct link, having no desire to attract said wingnuts: curious readers can find it on google here).

The first thing you notice on walking into the Courthouse is Kate Davis' stunning design: the entire stage is curtained in white fabric, lit inside to give a faint, soft luminosity. The curtains open to reveal a two-level stage painted antiseptic white: there's a broad area front stage, in which is suspended a miscellany of window frames, and a narrow area back-stage, across which is a huge image of a mountain range. The mountains seemed to me a mistake; while they simultaneously conjure the travel-brochure asppirations of Mark and Mandy and Gary's ascetic fantasies of Bin Laden, they seemed an unnecessary illustration in a set that was otherwise a beautiful theatrical abstraction.

Syd Brisbane uses the set imaginatively, and elicits committed performances from his cast. I was particularly impressed by Kevin Hopkins, whose unhappy smile becomes more and more painful, and Thomas Wright as the paranoid and brutalised Francis. Occasionally the direction wavers: when the actors dip their hands into buckets of blood and drip it onto the stage as they speak their final monologues, it struck me as naive theatrical metaphor (yes, we all have blood on our hands!) but, more importantly, it limits the actors' physical expressiveness. But this production's strengths well outweigh its weaknesses, and make this a show well worth a visit.

Ying Tong: A Walk With the Goons seems to invoke a very different world from Dennis Kelly's vision; but in fact, there are subterranean continuities. As any Goon nut knows (and I suppose, having been raised on BBC radio comedy, and being in possession of practically every text Spike Milligan ever published, I must count as one of those) the Goons' anarchic comedy was, among other things, a response to the trauma of World War 2 and the sheer bleakness of post-war Britain.

This was really a play that was waiting to be written, and clearly Roy Smiles was the man to do it. It threads Milligan's famous depressions - partly caused by his experiences as a soldier in Africa - into the manic comedy of the Goon Show. I expected a nostalgic evocation of the Goons, with the requisite imitations of Bluebottle, Eccles, Major Bloodknock and all the rest. A show, in short, that bought into the enduring popularity of this still wildly funny comedy, while gently reminding us of its darker currents...

And that is exactly what I got. But I was mistaken on one point: I thought this predictable recipe would add up to an excruciating evening. I was pleasantly surprised to find myself riding the Goon bandwagon with no signs of pain at all. This STC import is the best thing I've seen at the MTC for quite a while; it's stylishly directed and designed, and it's performed by a bunch of actors who look as if they're hugely enjoying themselves. And why not? It was probably once every British schoolboy's dream to be drinking "brown milk" (the brandy-laced milk they scoffed backstage) with Milligan (Geoff Kelso), Harry Secombe (Jonathan Biggins), Peter Sellers (David James), Wallace Greenslade (Tony Harvey) and the boys. It certainly was Prince Charles's.

Ying Tong opens with a re-enactment of a BBC radio recording, which was always performed in a theatre before a live audience. It's a clever device, because the audience immediately gets into the feel of the show and enthusiastically obeys the red APPLAUSE sign above the stage. I don't know if the script they perform is an actual Goon show or a Smiles imitation; if it's an imitation, I doff my hat, because it sounds completely authentic. The show is interrupted when Milligan suddenly freezes on stage, unable to speak; and then the red curtain rises to reveal the cavernous, shabby interior of a ward in a mental hospital.

The script switches between flashbacks and Milligan's rather confused present, in which he is visited by hallucinations that include, as well as the characters he and his fellows invented, a bunch of leprechauns, his ex-wife, and giant figures dressed as Morris dancers. There is one scene that is pure genius, where Jonathan Biggins channels Peter Seller's Dr Strangelove while giving Milligan a psychiatric examination. Here Smiles manages the collisions between reality, Milligan's imagination and the hallucinations of madness with a deft and unsettling hand: and Biggins' Dr Strangelove is pitch-perfect, sinister and hilarious.

Because it is about well-loved and recognisable public figures, a show of this kind is a bit peculiar: the actors are not so much acting as doing impersonations. So most of the time we are watching them being not-quite their models: it's not-quite Milligan, not-quite Bluebottle, etc. Fortunately the impersonations are good and the show is involving enough to get past this oddly alienating effect. I also discovered how deeply Milligan's writing has infected my consciousness (you can't get past that childhood conditioning): the play had an oddly patchwork effect for me, because I kept recognising the source material. But this recognition is also what gives this show much of its appeal: it's the next best thing to seeing the Goons themselves.

Michael-Scott-Mitchell's set deserves mention: he distorts perspective with a series of receding arches, which permits some interesting optical illusions that reflect the distortions of madness. In one scene, in fact, I was convinced that the actors were wearing stilts, because they looked like giants. And Richard Cottrell's direction is swift and sure, deftly exploiting the comic potential of the script.

It's by no means a profound play; Smiles skates along the surface of mental illness, exploiting its comedy and pathos rather than giving us a true picture of its hellish reality. Milligan wrote a couple of devastating pieces about his war experiences that are not drawn on here, but which suggest why it so haunted him. To bring out those truths would demand a very different kind of show, perhaps some kind of Beckettian monologue. But within its limitations, it's sensitively enough handled, and it's certainly a fun night.

I finished my week's theatre (whew!) with a visit to Circus Oz under the Big Top in Birrarung Marr Park, just past the ferris wheel. This is the next evolution of their Laughing at Gravity show, seen here last year: and it's hard to think of a better way to spend a chilly Sunday than whooping and cheering at Circus Oz while stuffing your face full of popcorn.

Under the Big Top serves up Circus Oz's trademark mixture of circus acts, cabaret and rock and roll. It's durable because it's enormous fun, with that necessary spice of voyeuristic danger. (The bendy pole act, for some reason, prompted every six year old in the tent to scream their lungs out in pre-emptive terror that the acrobat might fall down).

There are familiar acts well worth revisiting, given new twists: the mullet himself, Scott Hone, scarifying the youngsters with his BMX antics, and strongwoman Mel Fyfe having concrete blocks broken with a sledgehammer on her stomach. And the Singing Stuntman, Matt Wilson, is back with more bad puns, bringing his particular brand of clowning to trapeze and rope acts.

They're interspersed with some class new acts - the Pink Lemonade lady (Susina Wogayehu) who folds herself alarmingly into a glass box filled with pink liquid, or a wonderful Fred Astaire dance and juggling sequence. It's wicked, sexy and rude, with a feminist spin - courtesy of songstress Christa Hughes - that would warm the cockles of any old bluestocking's heart. Definitely a cheering antidote to a flu-ridden Melbourne winter.

Pictures: Top: Xavier Samuel in Osama The Hero; Bottom: Circus Oz performer Sosina Wogayehu shows how twisted she is.