Most summer volleyball is beach volleyball, but bringing it indoors (air conditioning?) is a great way to stay in shape for the summer.

The demand for summer gym activities seems to focus on basketball, but volleyball can serve more players (12 at at time vs. 10) and allows for play among people with different levels of skill, something that is really challenging with basketball.

All you need is some floor tape to lay out the volleyball court, along with a net and a ball and you are on your way.