Sideshow Bennie- eats fire, lays on a bed of nails, lets you throw darts at his back and more odd and interesting stuff.
Sid Haig- Devil's Rejects and many more movies. Nice guy in real life but crazy in the movies.
Enigma- Now this was a weird guy. Tattooed to look like a puzzle and than he "sang" and sucked Windex through his nose. Uhh, yeah..