I was a dancer captain last year and we had to stay up also (ha everyone would go in the back past the curtains and take like an hour nap. I dont know how your DM works, but for ours it was more activities then dancing so that kept people up and preoccupied. Also they had the doors open and every hour you'd learn the next step in a big line dance that was done at the end. There was no caffine or sugar allowed. What we did is got all the caffine that we could before hand. Not only did the 36 hours hurt but so did me having to work to work during the hours of the marathon