Porn mags (and a $300 bulletproof vest) saved Johnny Knoxville's life and paved the way for "Jackass." Tim Curry was originally cast as the Joker in "Batman: The Animated Series" before being replaced by Mark Hamill. Scott Bakula knew his Captain Archer had to fall somewhere between Chuck Yeager and James T. Kirk on the astronaut spectrum. What else don't you know about your favorite TV shows?