I ran Team Overbot.[1] We were way overdesigned for off-road and underdesigned for going fast.

[1] http://www.overbot.com

Same for us -- speed was not a consideration at all. We figured that if we could keep going and finish, we'd be one of the top 3 teams.

As it turned out, our mechanical engineering was great. What got us was software: we failed to free memory for passed obstacles, ran into memory exhaustion issues as a result and crashed out at mile 9. When we fixed the leak and reran the course, the truck finished in just over 7 hours.

It was an object lesson that garbage collection won't save you from memory-related issues. In retrospect, it was the also first time I ever encountered a million dollar bug. D'oh.

What was the second time?

I ran across quite a few of them while working tech at an investment bank. Never anything that resulted in direct losses, but implied missed revenue -- definitely.