"A Uniform Used to Mean Something," the year's funniest new movie so far, offers a rare opportunity to catch Jerry Seinfeld (search) at the top of his game - but it's watchable only on the Web.

Actually, calling it a movie may be overstating the case, since this small masterpiece that teams Seinfeld with an animated Superman (search) is only five minutes long - and is a commercial for Seinfeld's longtime patron, American Express (search).

Not that there's anything wrong with that.

In fact, there are more laughs in this ambitious short (or "Webisode") by Oscar-winning director Barry Levinson (search) ("Rain Man") than are in most feature-length comedies these days, including Levinson's upcoming "Envy" with Ben Stiller and Jack Black.

"Uniform" depicts Seinfeld and the Man of Steel - who uses that name to make restaurant reservations so they don't have to sit near the kitchen.

As voiced by Patrick Warburton (search) - who played Elaine's immortal ex-boyfriend Puddy on "Seinfeld" - and wittily animated by Radical Media, Superman has been re-imagined as an endearing, socially maladroit bumbler (not unlike George Costanza) who pretends to recognize a man he rescued years before.

Seinfeld declines Superman's suggestion for an activity - "cycling with you is no fun" - and suggests the Man of Steel help him hook up the speakers for his new DVD player.

Superman: "I've always wanted Surround Sound."

Seinfeld: "But you have super hearing."

Superman: "It's not the same thing. Surround Sound is like being there."

The two continue to bicker in classic "Seinfeld" fashion about reality TV shows and advertising blurbs outside a Broadway theater for a show called "Oh Yes, Wyoming!" until a robber steals Seinfeld's DVD player, oblivious to Superman's presence.

The contrite superhero tries to make amends, but Seinfield has a simpler solution involving his - surprise! - American Express card.

Unlike many sitcom stars - notably the "Friends" cast, who have appeared in countless dreadful movies - Seinfeld (who co-wrote the short with American Express' ad agency) realizes that his comedy works best in small doses.

And he's rich enough not to be seduced by Holly wood into thinking he's an actor.

Seinfeld's long-running AmEx commercials - including an earlier effort with Superman that aired during the 1998 Super Bowl - have always been a model of soft-sell wit, and it's good to see him venturing into something slightly more ambitious.

Seinfeld, Superman and Levinson have already wrapped a follow-up called "Hindsight is 20/20," in which our heroes are stranded in Death Valley.

Based on a brief preview on the Web site, we can't wait.