OK, I'm a little late on this, but in August this year I was convinced to participate in a 24 hour mountain bike race. We had a team of 8 guys; the race starts at noon on Saturday and goes until noon on Sunday. During the entire time, we always have a racer out on the course. So, yes, you do have to get up at 2 AM if it's your turn to take a lap.
How'd we do? We did OK. We finished 21 out of 90 teams in our category. You can see the results, we're team 260, the Flying Bisons. Flying Bison is a brewery and they sponsor us. They sent along 3 cases of their Aviator Red for our enjoyment.