Dancing rocks! (not a sport strictly speaking but you get physical exercise).

Ba that...

Squish is the best sport ever! It's a mutilated version of squash that involves four people to a squash court (at least!) and two or more balls.

Rules: When da ball comes at you. 'it it! HARD!
(Trying not to crane the person next to you!).
If the ball gets stuck in the ceiling/on a light etc. that constitutes a point. Requiring a new ball each time of course. One with the most points before we have to leave wins.

That's great fun! ..and looks pretty funny...
...especially when you try to do it in a suit.

-Pendragon