Want your show to last more than one season? How about 20? Either way, you have two options: Make sure you're an animated prime-time show that appeals to both children and adults or, better yet, make sure you've got a procedural on your hands with Dick Wolf or Jerry Bruckheimer backing you up. Here, the top 11 longest-running prime-time shows currently on air (ranked by years, not episode numbers). Why 11? We had to run long. . . .
1. "The Simpsons" (Fox), 1989-present (20 years)
2. "Law & Order" (NBC), 1990-present (19 years)
3. "South Park" (Comedy Central), 1997-present (12 years)