He was the contestant who couldn't be beat. For 75 straight episodes, Ken Jennings, a slight, sandy haired software engineer, was as much a fixture on Jeopardy! as host Alex Trebek. During his improbable stretch of dominance, Jennings obliterated the competition, racking up a staggering $2.5 million in winnings, including a record one-day haul of $75,000 in his 38th win (above). After some 2,700 correct replies, Jennings was finally ousted by a California real estate agent named Nancy Zerg. The answer that finally tripped Jennings up? "Most of this firm's 70,000 seasonal white-collar employees work only four months a year." As Zerg knew, it's H&R Block, not FedEx.