how many calories am I burning just standing around

I cannot say a whole bunch, but I have been rehearsing all week. I am in the superbowl halftime show, and it is a lot of stand and wait for 1.5 hours, then do your part, then wait an hour, then do your part, then wait an hour. My feet are killing me! And no break for snacks or sitting down or sleeping.. it's like a volunteer torture camp.