Stop at Nothing: The Lance Armstrong Story
That is a great one, sullly. I've watched it twice already. If Lance had not fallen from grace, he would have made a horrifically prosperous politician.
Another good "sports and drugs" documentary (also on Netflix) is called All This Mayhem which is about two Australian brothers, Tas and Ben Pappas, who became pro skateboarders in the 90s. Doesn't really paint Tony Hawk in a good light and is a much sadder, darker tale than Stop At Nothing, but still a really absorbing movie.