Fred Allen said that you can take all the sincerity in Hollywood, place it in the navel of a fruit fly, and still have room for three caraway seeds and a producer's heart.

This evaluation is a very popular saying in Hollywood itself, and every now and then someone from Hollywood will get disgusted with Hollywood and decide to take a pitiless, backstabbing, hilarious look at Hollywood.

This year's take on the Hollywood viper pit is Ben Stiller's “Tropic Thunder,” and it's a take-no-prisoners affair that can be counted on to offend just about anybody on it's way to some pretty hefty laughs.

The most visibly offensive component is the one you saw in the trailer: Robert Downey, Jr. plays a self-absorbed, five-time-Oscar-winning Aussie actor who undergoes surgical African-Americanization in order to play a Black soldier in an expensive Viet Nam epic. (Think “Apocalypse Now” on Jägermeister.)

This war film (titled “Tropic Thunder” just like the one we're talking about) is to be the come-back vehicle of action star Tugg Speedman (played by director Ben Stiller), whose career has tanked after an ill-advised Oscar grab playing a rural half-wit who talks to animals.

(This role, and frequent discussions thereof involving the term “retard,” constitute the second-most-castigated offense of this movie, when actually I think it's a jab at the actors who consider playing such roles a challenge: “I did the work,” says Tugg. “I watched a lot of retarded people.”)

The other soldiers on the team are played by Jack Black as a drugged-out fatty whose entire fame comes from flatulence; Jay Baruchel as the clueless newbie; and Brandon T. Jackson as an actual Black actor, whose running commentaries on Downey's fake Black actor are the only reason the script can get away with it – that and Downey's fatuous comments, an argot that any actor will recognize: “My tools are the mechanisms that trigger human emotion,” he intones to an interviewer.

Things heat up when the five actors are stranded in the Southeast Asian jungle at the suggestion of the book/screenplay author (Nick Nolte with hooks for both hands), a suggestion the poor British director, played by Steve Coogan, goes for, because he's about to be fired. After the director loses his head – and there's a visual joke that shouldn't have happened – the actors are on their own, and wander into the territory of a Burmese heroin-producing cartel run by a 12-year-old drug lord played by Brandon Soo Hoo, a great young actor who's destined for something, but I'm not sure what.

Here's where the movie, scripted by Stiller and two of his drinking buddies, wheezes down. As the actors finally realize they're in a life-or-death situation, the whole construct loses its point and becomes an excuse for explosions. The last gasp of real wit is when Downey admiringly critiques Tugg's command performance as Simple Jack in the druggers' camp; after that, it's action as usual on up to the finale of the heartwarming Oscar ceremony. There's even an unmistakable hommage to “The Bridge on the River Kwai,” but I bet David Lean never thought to almost destroy a cute little kid.

Possibly the most horrifying character in this gallery of horrors is the obscene brute of a producer called Les Grossman, who is in here so we can also offend Jews, as well as top the current record for f-word profanity, which I believe was held by...oh, I dunno – I lost count around “Scarface,” or maybe it was “South Park.” (Those darned kids!)

There is a marginal chance that you don't yet know who's playing Grossman, so I won't spoil it for you, but it's the first time I've seen “lead hair puncher” in the credits – that's the person who punches real hairs through the latex sheet that gets glued onto the smooth actor's chest and arms. If you still can't tell who plays Grossman, look at the tip of his nose: it's a dead giveaway.

Could it be this actor's first Oscar? I wouldn't be surprised.