Indiana Jones

In 1984 TSR produced an Indiana Jones tabletop roleplaying game that amongst it's list of copyrights and trade marks included Nazi^TM. This has infamously gone down in history as TSR (or LucasFilm) trademarking the word Nazi.

The actual reason is just as stupid but not quite as funny; LucasFilm insisted that every character from the films (Raiders Of The Lost Ark and Indiana Jones And The Temple Of Doom - the only two released at the time) be listed as trademarked. As one character was referred to in the script and credits as "Nazi", this character was included.