The Michigan one is talked about the most, but the two I've highlighted were the most painful for me to watch and I think we would have won both those games under current rules. I remember in the Wisconsin game, Mortensen got knocked out of the bounds on a scramble with about five minutes left in the game and under the rules then, the clock stopped. I believe under current (rules guys help me out) the clock wouldn't stop and, as a result, we could have probably wound things down. I could be be wrong on the rules thing. I just remember thinking after that play that time remaining might be a problem
It doesn't qualify as a collapse per se, but the Northwestern game in 2008 when Mike Kafka ran all over the field for over 200 yards and the Gophers lost on a pick-six on the last play of the game is the loss that is somehow burned most deep in my memory.