Rubeville, written and directed by Thomas Henning. Music by Liam Barton, Sebastian Steiger and Sean the Saw. With Gareth Davis, Dylan Young and Eloise Mignon. The Black Lung @ The Black Lung Theatre until October 15. Debris by Dennis Kelly, directed by Tanya Goldberg. With Thomas Campbell and Bojana Novakovic. Ride On @ the Black Lung Theatre, 55 High St Northcote, until October 14. Bookings: 8412 8777

"No other production this year," trumpets the press release for Rubeville, neatly undercutting its own hyperbole, "has combined these actors with these lines!" That's marketing for you, in all its empty seduction: the banal promise, so prinked up with exclamation marks that even its own mother can't recognise it. It's the hustle, the con, the sell, the miasma of delusion. At the centre of its fog of deception is the hustler himself, the most deluded of them all.

This is the world of Rubeville, where everything is for sale and nothing has any value. As it begins, this show reminds us that working in the theatre was once considered synonymous with prostitution: an abject Hernandez (Dylan Young), whom we have just seen begging on a street corner outside the theatre, offers himself to a member of the audience ("fifty dollars? ok, thirty five"), then pulls down his shorts and bends over the sofa.

A man with his shorts garlanding his naked bum has a certain grotesque pathos; but it becomes something else when Hernandez, playing out the imagined fantasies of his putative john, begins to sob, "Don't fuck me, please, don't fuck me". The voyeuristic horror of rape gives way almost at once to a lecture from "George Clooney", played by Gareth Davis, on what Hernandez (or Dylan Young) is doing wrong in his performance. "You want to please," says George (or Gareth). "You're pandering to the audience..."

I guess you could call what follows an extended mindfuck. A savage hour-long riff on the brutalisations of commodified celebrity culture, this is wickedly hilarious theatre, acutely self-aware and blackly intelligent. Thomas Henning and his cast pitilessly manipulate the expectations of their audience, invoking extremity only to explode it, turning in a trice from violence or pathos to outrageous comedy to sly commentary.

Rubeville is a sardonic response to the Americanisation of our culture, invoking the fantasy world of Hollywood and the seductive dream of a quick buck. The stage is littered with blank television sets, one of which neurotically plays a loop of random video footage: a close-up of George Clooney, some scenes from a black and white movie, film titles in a language which looks like Finnish. The band, playing Tom Waits-style blues/rock/folk, plays in the corner. Their faces are painted white and black in a sinister echo of blackface make-up, calling up the racial erasure of the Black and White Minstrels or the nationalistic mindlessness of football fans.

The plot, such as it is, concerns a series of get-rich-quick scams hatched by George Clooney, the self-proclaimed hustler, and his half-naked, filthy sidekick Hernandez. Trixie (Eloise Mignon), a junkie prostitute, ODs on their couch (but not before stepping out of character and complaining about the gender politics of the production, which means that the only woman in the cast is playing a junkie prostitute). They decide to make a quick buck by demanding ransom money from her rich family. Then they rip off the till of the theatre, in order to go to Iceland to claim Trixie's inheritance...

The nonsense of the plot is really a pretext. Rubeville is, among other things, a satire on theatre itself: theatrical conventions are invoked only to be undermined and attacked. The actors slip in and out of character, performing themselves as well as their roles, confusing the fictive reality of the show. It is completely unclear when the play begins or finishes. You walk into the theatre where the three-piece band is playing as George/Gareth scrambles over the seats, muttering incomprehensibly. Towards the end, George/Gareth confesses sadly that he has "run out of show". The final blackout, which prompts the audience applause and actorly bows, loses its finality when the actors come back on stage and start playing with the band, as if the bows were just another scene in this apparently improvised performance.

Rubeville makes me think of the sexually-charged anarchy of Heathcote Williams' play AC/DC, but it lacks Williams' utopian optimism. Like Williams, its destruction of the barriers between identities makes it genuinely Artaudian, and it is fuelled by a pervasive anger at the state of contemporary society. "Mediocrity and delusion," says the poet Hans Magnus Enzensberger, "stand in a complementary relationship to each other; their apparent antagonism conceal a deep-seated collusion. A social location which lies outside this entanglement will not be found." Rubeville is a spirited protest against both mediocrity and delusion, sardonically aware that, as members of a society which expresses its anxieties about identity in performances of violence, we are all implicated in their mutual machinations.

For all its apparent anarchy, this is highly polished theatre. All three actors generate rawly powerful performances with a risky improvisatory edge, but the real tell of this show is its sharpness: the timing is always impeccable. And did I say that it is hilarious? The Black Lung is evolving into one of the truly exciting nodes of theatre-making in Melbourne.

As well as being a theatre company, the Black Lung is a curated venue. For the Fringe Festival it has imported from Sydney Ride On's production of Debris, the debut play of British writer Dennis Kelly. First performed in 2003, Debris put Kelly in the company of playwrights like Mark Ravenhill, David Harrower and Sarah Kane, who are loosely grouped under the rubric of In-Yer-Face theatre.

It's easy to see why Debris attracted attention : it's a play that intriguingly combines high poetic language, drawn in part from Christian mystic traditions, with a hard-edged and blackly comic look at family dysfunction. It concerns a brother and sister, Michael (Thomas Campbell) and Michelle (Bojana Novakovic), who have been dragged up by their alcoholic father after the death of their mother. Oddly, for all its extremity the writing is apt to undercut its own emotional power by reaching too easily for a joke, but the energy and beauty of its writing is undeniable.

The play opens with a monologue by Michael, in which he describes how his father crucified himself in his living room on Michael's 16th birthday. The description of the (rather ingenious) self-crucifixion is at once funny and brutal, and the sensuality of its evocations of the dying father's flesh, filled with a kind of loathly eroticism, echo Julian of Norwich's descriptions of Christ's body on the Cross in her visionary work Revelations of Divine Love.

The mystic imagery recurs throughout the play, which tells a nightmare story of neglect and deprivation through a series of fragmentary scenes. The image of a lactating Christ, another common symbol in mediaeval mysticism, is resurrected in Michael's discovery of an abandoned newborn baby in the trash and his breastfeeding it with his blood. Against these macabre Christian manifestations, Kelly poses Michelle's various narratives of her mother's death and her own birth: in one, her mother dies of joy, choking on a chicken bone from a celebratory meal, and Michelle is ripped untimely from her womb; in another she gestates in her mother's corpse, which rots ignored in the corner of the living room, and turns into a nightmare carnivorous plant. These fictions, as becomes clear, are the means by which the children survive their upbringing.

Novakovic (most recently seen here in Eldorado and The Female of the Species) and Campbell are certainly up to the challenges of the script, and give powerful and nuanced performances as the two siblings. Unfortunately, Tanya Goldberg's direction lacks the bold imaginative flair of the writing: there is little sense of mise en scene, and the actors often seem awkwardly placed in the space.

The metaphor that stitches the production together - scene titles are chalked on the theatre walls by Novakovic, filling pre-drawn letter spaces like those in writing primers - also muddies the focus. Although it emphasises the childhood of the characters, the Brechtian allusion seems misplaced here, both theatrically and metaphorically - it is hard to see, for example, how this play is any kind of lesson, and the schoolroom reference, with its implications of orderly authority, has absolutely no connection to the disenfranchised lives the play portrays. For all that, it's a fair fist of a startling play, and more than worth the ticket price.

The Black Lung Theatre