The 12.3.08 edition of Jeopardy!, where everyone who hit a Daily Double chose to risk it all, has me curious how often that's happened and also how often the players would risk everything on all three DDs and question the answer correctly all three times.
For those who missed the eppy, the first two times it paid off and the third time, the man responded incorrectly and later replaced a vowel in Lt. Uhura's name and got himself into the minus where he remained and remains.