Trampoline - Seat Drop

Options
A friend and I both have trampolines in our backyards, and we began competing to see how many seat drops we could do. Although I am no where near her record (300) seat drops, I would like to know how many calories I burn after 5 min., non-stop.
Simple exercise, bounce, drop to butt, bounce back up to feet, then drop to butt again. This exercise is much more intense than jumping (30 cals. in 5 min.), I know, because i can barely breathe... which shows i need to work up to even 5 min.
ANYWAY... lol... any idea?