"The Simpsons" is much more than a show about the creatively told misadventures of Homer (voiced by Dan Castellaneta), Marge (Julie Kavner), Bart (Nancy Cartwright), Lisa (Yeardley Smith) and Maggie: It's also America's longest-running sitcom -- and for good reason. During the program's 18th hysterical season, Lisa befriends the son of a mob boss; Marge turns into Ms. Fix-It; peanuts are banned at school; and Homer enters basic training.