It's Ben 10 (http://www.cartoonnetwork.com/tv_shows/ben10/index.html), about a boy who is travelling the country in an RV with his grandpa Max and his cousin Gwen when he finds this mysterious meteor that fell from the sky. In it is this watch that attaches itself to Ben's wrist and gives him the ability to transform into different aliens. Ten, to begin with, but now it is much more. It is all the rage among boys Charlie's age.