OK, I've tried thinking about this long and hard, but I still can't come up with a good explanation behind the misspelling behind "Inglourious Basterds."
Here are a few possible explanations:
1) Tarantino was high when he came up with it.
2) Tarantino is an idiot savant who might be a wonderful writer but can't spell for shit -- and didn't have the heart to tell anybody that the only thing that needed to be spelled properly (the title) was wrong.*
3) The title is how Aldo the Apache would spell "Basterds" in his backwards-black-hills-of-Tennessee way.
4) "Basterds" -- with the emphasis on the "e" -- is how Eli Roth would say it when he was playing the Italian in the theater.
5) Mere perversity.
6) Tarantino made a bet with Harvey Weinstein that went something like this. "Watch, I'll bet you 50 buck that if I go ahead and fuck up the spelling of the title, everybody will run around in circles for months trying to figure it out."
If anybody's got an alternative idea, I'd like to hear it. Email email@example.com
* I actually think this is a credible scenario. Obviously, Tarantino is one of the most vain film directors on the planet. And I suspect that he's not such a good speller. If you saw the movie "Death Proof" one of the characters sends a text message to her boyfriend reading "your a asshole." Of course, it should be "You're an asshole."