Rico sure hopes it's funny

According to the MSNBC review:

One of the more outrageous conceits of the new comedy Tropic Thunder involves Robert Downey, Jr.’s performance as Australian actor Kirk Lazarus, who undergoes a controversial skin pigmentation surgery to play an African-American soldier in the Vietnam epic movie-within-the-movie. (Shades of, say, Christian Bale losing lots of weight for The Machinist or Robert De Niro putting on the pounds for Raging Bull.) Hollywood has a fairly despicable history of casting Caucasians as ethnic minorities.
Tropic Thunder, at least, is making fun of the practice, but in these movies, it was no joke at all:

The Jazz Singer (1927): In this legendary first talkie, Al Jolson plays a singer torn between hot-cha Jazz Age nightclubs and his legacy as the son of a Jewish cantor. In one famous sequence, he dons burnt-cork blackface to sing Mammy.Giving the old movie a little credit, vaudeville performers of the era were still doing this kind of performing, but it’s hard to watch through contemporary eyes. And modern standards certainly didn’t stop Neil Diamond from also putting on blackface for the opening number of the 1980 Jazz Singer remake.

Holiday Inn (1942): Wondering why this musical starring Bing Crosby and Fred Astaire, about a hotel that’s only open during holidays, doesn’t get as much TV play as its quasi-remake, White Christmas? Probably because of the Lincoln’s Birthday number, Abraham, which involves an all-white chorus of singers and dancers wearing blackface to portray liberated slaves.

Charlie Chan: Hollywood’s most infamous — although far from its only — example of 'yellowface' comes from this series of films about the legendarily wily Chinese-American detective created by author Earl Derr Biggers. Apart from a few early silent forays, these films featured Chan being played by the likes of Warner Oland (born in Sweden), Sidney Toler, and Roland Withers. And lest you think Neil Diamond was the only actor embarrassing himself racially during the Reagan years, check out 1981’s Charlie Chan and the Curse of the Dragon Queen, starring the oh-so-British Peter Ustinov as the famous private eye. To this day, about the only time Chan has been played by an actual Chinese actor was in the goofy 1970s Hanna-Barbera cartoon The Amazing Chan and the Chan Clan, where he was voiced by Keye Luke, who played 'Number One Son' in several Chan films, and (much later) the Master in the Kung Fu series with David Carradine.

Taza, Son of Cochise (1954): Rock Hudson. In the title role of a Native American. In 3-D.

The Conqueror (1956): While this legendary flop is most famous for its tragic aftermath — much of the shooting occurred downwind from a nuclear test site in Utah, resulting in much of the cast and crew eventually dying of cancer — The Conqueror also provides a cavalcade of ridiculous racial impersonations. Anglo actors John Wayne (as Genghis Khan) and Agnes Moorehead, alongside Mexican performers like Pedro Armendáriz, play Mongols, while red-headed Susan Hayward tries to convince us that she’s a Tartar princess.

Soul Man (1986): This comedy’s heart was mostly in the right place, but given the amount of controversy it stirred up when it was released, it’s worth mentioning here. C. Thomas Howell plays a college student who can’t afford to attend Harvard Law unless he can snag a minority scholarship, so he overdoses on tanning pills and makes himself 'black'. The idea might sound offensive on its face, but Soul Man actually teaches Howell’s character one lesson after another about the realities of stereotyping — his preppy fellow students assume he’s good as basketball, he gets arrested for 'driving while black' — and two of the film’s best performances come from Rae Dawn Chong and James Earl Jones. It’s by no means a perfect movie, but it’s one that’s smarter about race that many were willing to assume.

South Pacific (1958) and Flower Drum Song (1961): The big-screen versions of these Rodgers and Hammerstein musicals prove that yellowface isn’t just for white performers. Juanita Hall played Pacific Islander 'Bloody Mary' in the former and Chinese-American 'Auntie Liang' in the latter, but Hall herself was African-American.

Dragon Seed (1944): Katharine Hepburn and Walter Huston. As Chinese villagers.

Breakfast at Tiffany’s (1961): It’s a testament to how great everything else — from the screenplay to the score to the performances — is in this movie that Tiffany’s managed to become a classic despite the presence of Mickey Rooney as Japanese landlord Mr. Yunioshi. Whatever the Asian equivalent to shucking and jiving is, Rooney does it here, complete with big glasses, buck teeth and the mangling of his l’s and r’s. (“Miss Gorightry! I must plotest!”) There’s a great scene in Dragon: The Bruce Lee Story where Lee and his date walk out of the movie during one of Rooney’s scenes, and no doubt many Tiffany’s lovers fast-forward through his embarrassing and racist mugging.

Teahouse of the August Moon (1956): Ah, but the lure of yellowface was apparently hard to resist, even among our most distinguished performers. Marlon Brando lobbied hard to play the Japanese character Sakini in the adaptation of the Broadway play, and he even received top billing. Brando’s work is certainly a step above Rooney’s, but it’s not a performance that has aged well, for obvious reasons.

Lost Horizon (1973): John Gielgud. As a Tibetan.

Bamboozled (2000): More scattershot than Tropic Thunder but far more scathing, Spike Lee’s satirical comedy provides an interesting history lesson about blackface performance in this country while simultaneously commenting on contemporary African-American images in pop culture. It’s not one of Lee’s most focused movies, but it’s one of his most blistering.

Rico says the best in the genre has to be, still, Putney Swope; if you've never seen it (and most people haven't), get it from Netflix...