Simon Munnery, Soho Theatre

Bubbles are emanating from Simon Munnery's head. They're streaming out of a huge, black stovepipe hat which he has cobbled together from cardboard and sticky tape. He has also slung an electric guitar over his shoulder as he sidles up to the mic to begin Hats Off to the 101ers, and Other Material. What does he look like? A cranky mishmash. Kids' entertainer or mad Victorian undertaker?

His gigs defy narrow categorisation too, being experimentally varied and full of non-sequiturs. One minute he'll be launching into a satirical droning ballad – "la la la, lighter than air" – telling the story of the R101, the grandiose 1930s British airship that got off the ground only to nosedive immediately. Munnery also tries to recreate the R101 with a plastic sack and a hairdryer. On the night I saw the show, the sack melted. He was quick to point out that this "complete disaster was historically accurate".

Moving swiftly on, he throws in a snatch of video projection: a spoof Gillette razor advert but in the style of an old, silver-screen cowboy film. Soon he veers off at a literary-critical tangent, to dissect Bruce Springsteen's macho lyrics. Next thing you know, he's offering to imitate any car horn the audience care to name. He'll also tell a few observational anecdotes, about his childhood or about an oldster he saw in the street, not just waving his walking stick at aggressive motorists but pretending to machine-gun them down with it.

In the course of the evening, Munnery will also turn performance poet and character comic (adopting cockney and pedantically eloquent personae). And there's wacky puppeteering (an irreligious natter on Golgotha with cardboard cut-outs).

Hats Off, it must be said, is not hilarious at first. The rhyming doggerel of the R101 ballad ("Surely we'll crash/Balderdash" etc) seems a tad puerile. Has Munnery – of Attention Scum and Alan Parker, Urban Warrior acclaim – lost his edge? There are patches where he seems uncharacteristically bland, not least resorting to the clichéd standup routine of asking if any punters are in from a particular city. More tightening and paring is needed, been this show has been around for a while.

That said, this comedian is more at ease and likeable than he used to be. He's palpably enjoying himself and, as the show proceeds, the material gets better rather than bombing. Munnery particularly excels in his fanciful set-piece monologues. There a wonderfully surreal passage where, in the manner of a pukka battlefield commander, he mutters about lice invading his eyebrows. And there's a terrifically clever and funny "Women's Studies" lecture, delivered by a boob-obsessed chauvinist. This is academia's answer to Al Murray's Pub Landlord: contriving to be both unPC and subtly PC. Worth catching.

• Simon Munnery is at Soho Theatre tonight, and touring until 23 March