One of my all time favorites is one most never heard of, Jochen Rendt. He drove for Lotus in the sixties.
On one of the rare occasions a Formula One race was on TV, Wide World of Sports was carrying the 1970 Monaco GP. Its a tight street circuit and late in the race, Sir Jack Brabham had a major lead and was cruising to a win. Back in the pack, Rendt just decided to go for broke and was driving like a maniac, drifting through the turns, making wild passes.The cameras picked up on the charge and started to cover him and in a few laps, it was clear he was going to catch up to Brabham. Brabham couldn't see him coming in his mirrors as the course is so tight and there were no radios so his team couldn't warn him.
Rendt showed up out of nowhere, pressured Brabham into an error in the final turn, and passed Brabham on the last lap to win. Haven't seen a better F1 drive before or since.
http://www.youtube.com/watch?v=XC2v4A_y4VI