The difference between gangsters and gangstas 

Character actor (n.): An actor who specializes in playing the roles of unusual or distinctive characters.

That barebones definition comes courtesy of my late '90s Powerbook. I would also add that a character actor almost always boasts a mug instead of a puss, and many leading men (i.e. Pitt and DiCaprio) regret not being ugly enough to land the dishy parts that the character actors gnaw on (I know: boo hoo). A character actor just shows up, steals a few scenes, cashes a plump check, and then it's onto the next shoot.

Take, for instance, veteran English character actor Michael Gambon. You may not know the name but you've seen him around. Whether he's channeling a crimelord in the sly British gangster flick Layer Cake or gamely playing straight man to the supremely silly Ali G in Ali G Indahouse, Gambon lends everything he participates in an air of gritty class.

The "hero" of Layer Cake, portrayed by Daniel Craig (The Mother), doesn't have a name. XXXX, as he's called in the credits, is a careful and successful drug dealer on the hunt for that final lucrative payday. His shifty boss Jimmy (Kenneth Cranham) seems amenable to XXXX's retirement plan, but there's a problem. The daughter of Jimmy's boss, kingpin Eddie Temple (the cool Gambon), has gone missing from rehab, and Jimmy wants XXXX to find her.

Distracting XXXX from this task is the million pounds' worth of Ecstasy that a volatile loudmouth called The Duke (an entertaining Jamie Forman) has liberated from some cutthroat Serbians. XXXX wants them. Jimmy wants them. Temple wants them, too. But The Duke wants too much for them. And the Serbs really, really want them back.

The always-captivating Craig is reportedly in the running to be the next James Bond, a role that he is all wrong for yet probably would not decline if offered (it's definitely an attractive albatross). Also on hand is the essential Irish actor Colm Meaney (InterMission) as Gene, Jimmy's trusted lieutenant and a man who knows on which side his bread is buttered.

Layer Cake is the directorial debut of Matthew Vaughn, who produced all of Guy Ritchie's films (the decent Lock, Stock and Two Smoking Barrels; the overrated Snatch; and cinematic punchline Swept Away). Vaughn was obviously taking notes during those productions, since he shares Ritchie's flair for the visual (the scene transitions are superb), ear for crackling dialogue, and gift for soundtrack selections (including The Cult and my very favorite Stones song). What Vaughn possesses that Ritchie has not yet exhibited, however, is gravitas and restraint, making Layer Cake more of a cautionary tale than a gleeful glamorization of thug life.

Restraint, however, can be an overrated virtue, and fortunately it's one that Sacha Baron Cohen doesn't possess. Cohen's shrewd comic creation Ali G makes his feature-film debut in Ali G Indahouse, a thoroughly unnecessary and extremely funny collection of lowbrow jokes and sledgehammer sight gags about a clueless wannabe gangsta stumbling through the corridors of power while completely baked.

Ali G lives in the middle-class suburb of Staines with his Nan and hangs out with his posse of pasty white men. He's in a tizzy because of the imminent closing of the local community center, a place he describes as "what Mecca is to the Jews." So he embarks on an abbreviated hunger strike ("just like Martin Luther Vandross") that catches the eye of the deputy prime minister (Charles Dance), a man "even more eviler than Skeletor." The deputy is looking to take down the prime minister (Gambon) and needs a candidate for MP that will make the prime minister look incompetent. Guess who he chooses?

The thing I love about Cohen is he throws himself into his characters with such infectious gusto. He will seemingly do or say anything for a laugh, no matter how embarrassing (witness Ali G's heretofore unknown Goth past). Keep an eye out for Martin Freeman (Tim from the superior BBC version of The Office, as well as The Hitchhiker's Guide to the Galaxy) as Ali G's right-hand man. And Gambon is an awfully good sport, especially in the hilarious scene with the African leader that devolves into the crudest of misunderstandings.

Another advantage of being a character actor is that a talented one can work as long as he wishes. Next up for the retirement-age Michael Gambon is another stint wearing the robes of Professor Dumbledore in the upcoming Harry Potter and the Junior Prom. (I'm actually just guessing at the title, but that kid is certainly due for a little fun.)

Layer Cake (R) opens Friday, June 3, at the Little Theatre. | Ali G Indahouse(R) screens Friday, June 3, (a Rochester premiere) at the Dryden Theatre, George Eastman House, at 8 p.m.