As a subculture, stand-up comics are a lot like boxers--highly competitive but united by their love of the art--and this superlative documentary by Christian Charles delves into the world of stand-up with a seriousness and attention to detail matched only by Phil Berger's book The Last Laugh. After wrapping up his phenomenally successful sitcom and retiring his old act on an HBO special, Jerry Seinfeld went back to the clubs to come up with an hour of new material, a grinding and emotionally draining process that took about a year and taught him that the goodwill accorded him as a beloved TV figure expires after about five minutes onstage. Interwoven with Seinfeld's odyssey is that of Orny Adams, a rising star so hungry for fame he can barely sit still, yet as the older comedian's experience proves, no amount of success can alleviate the self-doubt that seems to gnaw at every great comic. The numerous bull sessions are both illuminating and hilarious, pulling in such talents as Colin Quinn, Garry Shandling, Robert Klein, Chris Rock, Jay Leno, and Bill Cosby, whose ability to keep it rolling onstage for two and a half hours at age 63 provides his juniors a humbling example. 82 min. 900 N. Michigan, Webster Place.