My favorite was when our team almost... almost... became the first team to score autonomously at the Portland regional playing Rack'n'Roll. A bit of a malfunction in our ultrasonic rangefinders, combined with a bit of over confidence in our mecanum drive code... and if only we'd let go of the tube. It was match #2, in front of the entire stadium in Portland, on the first weekend of competition.
Start the match... burn three doughnuts, then score a tube right in front of all the judges. If only we'd let go, it would have been so, so sweet.
http://www.thebluealliance.com/match/2007or_qm2
Jason