Here's a look at 'Today in Rock History' featuring: Will Poulter is 27. He was Kenny the virgin in "We're the Millers." Sarah McLachlan is 52. Singer whose main talent is making people feel sorry for stray kittens and abused beagles. Today in 1974, Muhammed Ali beat Joe Frazier at Madison Square Garden in their second match of three fights. Frazier had won the first one. In 1986, The Space Shuttle Challenger exploded. It happened 73 seconds after liftoff, and killed all seven crew members: flight commander Dick Scobee; pilot Michael Smith; Ronald McNair; Ellison Ozinuka; Judith Resnik; Gregory Jarvis; and schoolteacher Christa McAuliffe.
