The comedian Andy Kaufman was perpetually aware that a performance was not just a piece of material, but an event, happening in a time and place. He wanted his audiences to have an experience; to know they were in the room, watching somebody putting on a show. People didn't always applaud his outrageousness as they watched it, but he always got laughs somehow. Maybe they would laugh AT him. Or chuckle afterward, in disbelief. Or make their friends crack up by telling them what he did. The sheer lunacy and audacity of his acts was hilarious; maybe not first-hand, but certainly in concept, when you stopped to think about them.

After all, Kaufman is the guy who once went onstage, read "The Great Gatsby" in its entirety, then walked off. Whose act once consisted of standing in silence through the "Mighty Mouse" theme song, except for the "Here I come to save the day!" line, which he'd mouth along to. And who, to close a concert in the gigantic Carnegie Hall, took all the spectators out for milk and cookies. Kaufman was always pulling gags you had to experience, even if that required you to be the butt of them. When he died of cancer in 1984, many thought it was just another practical joke.

There are of course those who hail him as a genius. His detractors find him confounding. Future generations can make up their minds by watching Miloš Forman's "Man on the Moon", a film which some have described, unfairly, as a sort of Greatest Hits compilation reel. Yes, the film has a straightforward structure in chronological order, and is mostly made up of its hero's onstage appearances. But it is therefore a faithful and successful presentation of a very interesting character, leaving us to love or hate him at will. The surprising thing is that so many of Kaufman's antics are amusing in themselves, and not just as ideas. This is a very funny picture.

It's also a deeply moving screen biography, following years of success right through to times of pain, and made by some of the masters of the bio-pic genre. Forman, the director, was also the helmsman on the Oscar-winning Mozart epic "Amadeus" (1984), as well as "The People Vs. Larry Flynt" (1996), a movie about the controversial publisher of "Hustler" magazine. The screenwriters, Scott Alexander and Larry Karszewski, wrote both "Flynt" and "Ed Wood" (1994). And Jim Carrey is a terrific choice for the starring role. It's his second performance as a dramatic lead, and he proves that his turn in "The Truman Show" was no flash in the pan, letting his eyes and voice become possessed by his character. His appearance always seems a little odd, but that's kinda the point. Anybody who knew Andy Kaufman will tell you that he was always "on"; his mind was always pushing something new up his sleeve, he made you keep your guard up. "There is no real you," one of the characters tells him. That character is his wife.

Of course the essential problem with any film about this man is that it explains somebody who refused to be explained. Figuring out what Kaufman was up to was part of the fun. Then again, on his deathbed he did ask for a movie to be made about his life. Maybe he did think it was important to be understood. He just thought that speaking for himself would be a cop-out.