I was about to post that I'm surprised nobody has mentioned this series.
I just watched the one on Hansie Cronje, and although it seemed a little rushed, it really is a sad story of how money can completely take over one's thinking, especially one in a power position as Hansie was at the time (late 90's to 2000).
He was completely infallible both on and off the pitch (so it seemed), all it took was 3 days lost to rain in a test against England, a phone call from a bookmaker, and boom - his life was never the same until his death in 2002.
The fact that Herschelle Gibbs was involved, but when it came to the crunch he couldn't go through with it was mindblowing, I don't ever recall him being involved or the implication that he was, but he was, he admits as much in the doco.