Disney commissioned a Peter-Pan prequel to hit up Broadway someday soon, according to Yahoo News (my third least favorite thing.)
Indiana Jones and the Temple of Doom
If you look at the dates on the bottom of the screen, you may notice that Temple of Doom happens BEFORE Raiders of the Lost Arc. There doesn't seem to be a POINT to having the movie be a prequel, but what are you gonna do? We certainly can agree that Temple of Doom is the worst or second to worst Indiana Jones movie.
Episodes I, II, and II
I'll note here, that I'm not counting Batman Begins or anything like that as a prequel. It's the first in a series, it's not going off of ANYTHING that had to do with the Tim Burton films of the 90's... it's not a prequel!
X-Men: First Class
Full of cheesy one-liners and underwear scenes; I already complained about this movie.
X-Men Beginnings: Wolverine
It was dull at times, and completely un-rewatchable, but it didn't make me want to burn down the theater after watching it.
The Good, The Bad, and The Ugly
Surprise!! If you weren't around in 1966, you might not have known that The Good, The Bad, and The Ugly came out AFTER A Fist Full of Dollars and For a Few Dollars More. The Good, The Bad, and The Ugly is my favorite western, naturally. The acting is fantastic. There's nothing like a good man-man movie.
Prequel to Silence of the Lambs. This movie was way better than its sequel friend Hannibal. NEVER see Hannibal. Just don't do it!
Aaaaaaaaaaaaaaand I can't think of any others right now. I invite you to complain about prequels you hate.