How to get exercise? I'm at school from 6am-6pm

Hi! I'm at school from 6am to 6pm everyday for school and then play rehearsals. Afterwards I have homework and Bible study, and I have to be in bed by 9pm. What are some easy workouts I could do to keep up some sort of a routine on school days. We aren't in PE right now, we're in health.

Ideas?