If you only see one stand-up comedy set at this year's Fringe, it should probably be Andy Zaltzman. Although I can't claim to have seen everything on offer, I'd be willing to bet there are more punchlines per minute in his hour of material than in the rest of the shows on his page of the programme combined. Conversely, it's hard to know where to start describing it, in the way that it's hard to describe large, complex, scientific issues like the formation of the universe or why there isn't a third series of Spaced. What sticks with you about the show isn't jokes so much as a general sense that comedy exists for an important curative social purpose, and that Andy Zaltzman is one of the best people in the country to administer that cure (as well as one of the most disturbing to see upon coming round from the anaesthetic.) There are jokes here – lots of them. Jokes about politics, jokes about 90’s golf players being 'presumed warlords', jokes about talk radio, and jokes about having a Jewish dog. Many are in an insanely long pre-show monologue played over the venue speakers, which makes it even harder to remember them all; but given that it's Zaltzman's relentless linguistic dexterity that makes them possible in the first place, perhaps the hardest thing of all is to rephrase. My favourite part – a deconstruction of the myth of the 'invisible hand' of the financial markets, in which Zaltzman suggests the astounding potential to steal and screw accorded to any owner of an invisible hand – in any words but his own doesn't even come close. This isn't, it must be admitted, a highly-structured show; anything with what seems like ten minutes of new material about the nationwide rioting, written that day, would have a hard job retaining any kind of neat, narrative shape. Instead, it's an hour of a man with a laser-sharp eye for political folly and a rotten sweet-tooth for horrendous puns making you laugh so often you can barely keep up with what you thought was funny twenty seconds ago. Andy Zaltzman is wasted on rooms this size – but what British TV channel is currently going to commission topical comedy this incisive?