Since age ten, Dave "Miracle Boy" Mirra has been defying gravity and changing people's minds about what can and can't be done on a bike. But in 1993 he lived up to his nickname in ways that his fans could never have anticipated. Six months after he was injured by a drunk driver and told by his doctors that he would never ride again, he was back on his bike, competing in -- and winning -- high-profile BMX events. Since then he has gone on to win...