I'm not sure how well it's being reported, but there have been a few disqualifications for doping at the Olympics. The always above-board DPRK lost both a bronze and silver medal after testing positive:
BEIJING - Kim Jong-su of the Democratic People's Republic of Korea (DPRK) has tested positive for doping at the ongoing Beijing Olympic Games, the International Olympic Committee (IOC) said here on Friday at a press conference.
What struck me as odd were the events he won medals in: