Comedy: Rick Shapiro, The Green Room, Edinburgh

The Green Room must feel like a home from home to many of the American comics who are appearing there, resembling as it does some kind of underground New York art gallery. Coincidentally, it was at a benefit gig in CBGBs Gallery on the Bowery where I last saw Rick Shapiro in 2004. His ranty antics baffled the room so much so that Robert Newman, who was also on the bill, asked for a break so he could bring the energy back into the room before he went on.

Tonight Shapiro is as baffled as his audience was then, admitting "I'm not even here yet", but the erratic nature that made fellow American Doug Stanhope veer from genius to ludicrous last year is all part of the Shapiro shtick. Raddled and wiry, wearing a vest, a cap (initially) and a the close-shaven outline of a walrus-like moustache Shapiro looks like a cross between Easy Rider and Smokey and The Bandit.

"Leafy green veg, leafy green veg, mmm, leafy green veg, God I miss syphilis," begins Shapiro seemingly of nowhere, a stream of consciousness overflow that later leads into routines about food fads ("Upscale deli? It's just a deli. Upscale deli sounds like you are inviting the pig to be in your sandwich") and sex ("ever cheat on your girlfriend and it felt bad after about the 17th time?").

His other preoccupation is Republicans. "Sometimes you have to have 14 Vietnams in a row," he imagines one telling him to justify the Iraq war. Not that he holds out much hope that a change in administration will help, accusing both of the Democratic front-runners Hillary Clinton and Barack Obama of being "both white men".

Some audience members would probably have been surprised to learn that this grizzled, uncompromising character has already been reigned in by television, appearing in the Chris Rock collaborator Louis CK's HBO sitcom Lucky Louie, though it was cancelled after one season.

All the more reason, perhaps, for the extra bile he has for the entertainment industry, especially film, as he launches into a trailer announcer tirade: "Mark Wahlberg tries to act... Bruce Willis as Bruce Willis is Bruce Willis, Robin Williams will always be a self-parody." Unsurprisingly Harry Potter fans are not left unscathed either.

Despite his take-no-prisoners attitude, being locked in a small room with Shaprio is not quite as terrifying as one might imagine. He is reasonably lascivious towards female members of the audience but, like Jerry Sadowitz, gives the self-defence that he is really not that bad. After all, he pets cats. "Look, this is a petting movement," he says while moving his cupped hand from side to side, "that's real, you can't fake that."

Shapiro's first gig at Glasgow's Stand comedy club last week went down a storm, with one person left bent double, crying with laughter. There were no casualties tonight but Shapiro left an impression all the same.

To 26 August, not 13 (0131 220 0885)