Here's your daily look at 'Today in Rock History' featuring: Hayden Panettiere is 30. She was Juliette Barnes on "Nashville." Usain Bolt is 33. Jamaican sprinter who was once the Fastest Man Alive. System of a Down superstar, Serj Tankianis 52. Jim McMahon is 60. The NFL veteran who's already dealing with early-onset dementia, thanks to the beatings he took during his football career. Remember the "Super Bowl Shuffle"? I DO. But he might not.