Awesome, Dear Boy: Til Schweiger had refused to wear Nazi uniforms in films before. He took the role of Hugo Stiglitz because he'd get to kill Nazis in the film.
Bonus Material: Nation's Pride is included in its entirety on the DVD.
The Cast Showoff: Christoph Waltz and Diane Kruger are both fluent in English and French in addition to their native German. Waltz speaks all three in the film, in addition to Italian. He speaks some Hebrew, too. Kruger speaks English and German alternately throughout the film and has to affect a thick German accent because her natural speech nearly lacks one.
The Indian-American Omar Doom plays the Jewish-American soldier Omar Ulmer.
Fatal Method Acting: A near miss. During the climactic scene, the fire raging through the cinema was completely real. Unfortunately, it began to get out of hand, and the two actors in the scene were only wearing a jelly to protect their skin; the rest of the crew had fire suits. Ten seconds after Quentin Tarantino called 'cut' and everyone rushed off, the platform the actors had been standing on collapsed. The heat was so intense (2000 degrees fahrenheit) one of them passed out afterwards.
Melanie Laurent worked as a film projectionist for weeks to prepare for her role.
Eli Roth joked that the period clothing helped make him especially aggressive, saying "wearing wool underwear will make you want to kill anything". His girlfriend also added Hannah Montana music onto his iPod to Troll him, which helped get him angry enough.
Tarantino himself choked Diane Kruger for real for the close-up shots of Bridget von Hammersmark's death to get a realistic reaction.
The Other Marty: Simon Pegg was cast as Lt. Archie Hicox but dropped out right before filming began due to scheduling conflicts with The Adventures of Tintin. Michael Fassbender then replaced him.
Similarly Named Works: The "Inglourious Basterds" misspelling was likely to avoid a lawsuit by the copyright holders of the 1978 film "The Inglorious Bastards", which was also a World War II film. Though it might also be a reflection on Raine's education.
At one point Ennio Morricone was onboard to compose the score but backed out due to his belief that he would be unable to work efficiently in the amount of time given.
In the screenplay, the first part of the film set in Paris was intended to have been filmed in black and white, using entirely natural lighting, in reference to the French New Wave.
As Quentin has noted, he at one point responded to the length of the material he'd written with a decision to make it a miniseries. As it stands, he's noted that he has enough for a second film, which he may or may not make eventually.
Michael Madsen was slated to appear as a character called Babe Buchinsky, but did not appear in the final film.
Jean Reno was the original choice for Perrier LaPadite.
Nastassja Kinski was in talks for Bridget Von Hammersmark; Tarantino even flew to Germany to meet the actress, but a deal wasn't reached.
The original draft of the script had Shoshanna as a far more active member of the French resistance, sniping at Nazis from rooftops and even having a kill list of known German officials. But when Tarantino made Kill Bill, those details were worked into the film, and he felt it was more in character for Shoshanna to keep a low profile.
The original draft also had Wilhelm surviving being shot by Bridget von Hammersmark, and he would tell Landa that she was the double agent.