Circus Oz: Laughing at Gravity tour. With Svetlana Bunic, Stuart Christie, Jim Dunlop, Mel Fyfe, Sharon Gruenert, Scott Hone, Christa Hughes, Michael Ling, John O'Hagan, Ruby Rowat, Matt Wilson and Sosina Wogayehu. At the Big Top at Birrarung Marr until July 9.

I have been very spoilt in the past couple of weeks. It is as if Melbourne theatre has decided to show me the best it has to offer, from its tiny alternative theatres to its main stages. And then, just to remind me that vital theatre isn't exactly a new thing here, I found myself in the Big Top at Birrarung Marr, just off Federation Square, watching Circus Oz's latest show.

Circuz Oz is the longest lived act to spring out of the energies that drove Melbourne theatre in the 1970s. It was formed in late 1977 out of two smaller circuses - the Soapbox Circus, out of the seminal Australian Performing Group, and the New Ensemble Circus from Adelaide - and it influentially redefined modern circus by mounting animal-free acts that combined rock and roll, popular theatre, cabaret and satire with traditional circus acts.

Circus Oz blazed the way for the alternative circuses of the 1980s, such as Cirque du Soleil, Ra Ra Zoo and Archaos. Over almost three decades as one of our most popular exports it has continually reinvented itself, but through its many incarnations and a few longueurs the company has stuck close to its central ideals. Overtly political, defiantly anti-hierachical (even the stagehands, dressed as over-the-top ninjas, get a gig in this show) and exuberantly, unashamedly Australian, it is the apogee of the larrikin physical theatre that defined our theatre in the 1970s.

As its Laughing at Gravity tour demonstrates, there's a lot of life in the old dog yet. And let's face it, it's fun going to see something at the Big Top. There's a band at the back of the stage manned by outlandishly dressed clowns, the players in their candy-coloured costumes are chatting up the audience, there's fairy floss and popcorn and chips, and the excitement is palpable. And then the show starts.

The hallmark of Circus Oz has always been the original spin they put on their acts. Here it's acrobatics to deafening hard rock, or trapeze artists dressed as kids from high school coming on to a soundtrack of AC/DC and the Ramones. Or there's Scott Hone, the best mullet in the business, scarifying young audience members by screaming towards them full-pelt on his BMX, only to twist away at the last moment, as he charges two matadors (one with an accordion). Or the anarchic performance of the 1812 Overture, where the conductor is swung up into the air and is pursued by a double bass.

Christa Hughes from Machine Gun Fellatio brings a sexy dash of cabaret with her shiny banana-yellow tails and banana microphone. And Matt Wilson, who is surely one of the most physically adept clowns around, is everywhere - as the Singing Stuntman, or jumping from a ladder into a grand piano as he causes mayhem in the orchestra, or wowing us all with his Pegs! Of! Pain! (he pins clothespegs all over his face, including on his tongue). Well, I guess you have to be there for that one. But it reminded me of the comedy duo Tick Where Applicable, Tim Scally and Steven Sculley, who would torment their faces with rubber bands to grotesque and comic effect.

An acrobatic satire of our august Parliament, reminders about the value of tolerance, and a collection at the end for asylum seekers give the comedy a bit of contemporary bite, but it's a political message that comes wrapped like a bonbon. The only problem is a murky sound system, which takes the edge off what sounded like some topical jokes.

The sets are designed by Anna Tregloan (who along with Adam Gardnir seems to be designing practically every show in Melbourne) and it looks like, well, a circus, but with a twist. The acts are spectacular, and the ending is a pyromaniac's dream. I enjoyed it as much as my eleven year old son, and he was incandescent.