fun games:
Jailbreak dodge ball --
gym is split down the middle, with no man zone in the center, and jails in the back. If you're pegged, or someone catches your toss, then you're sent to the prison on the other side. Your team throws footballs to you to get out. If they make it through the basket it's a jailbreak and everyone is free.
Pacman --
There are a bunch of line in the gym, and some are manual added with tape. You have to stay on the lines as and about 6 people are ghosts. If they tag you, then you have to sit down and you block any travel. The idea was the survive the longest, but it was cool, because you could trap ghosts if you had some sacrifices.
Crab Soccer --
You crabwalk the entire field, and earth balls are sent into play. You can only use your feet to move them, and it basically involved punting the ship out of a giant inflatable ball and hoping it ended up reaching the enemy goal
Mat Ball --
The only real game we played in middle school, and the most fun. Mats were placed at the four gym corners as the bases. You'd be pitched a volley ball, and if the ball hit the back wall it'd count as X number of runs (depending on where you hit) plus everyone on base. You could stack as many people as you wanted on base, and if you stepped off you couldn't step back on. There was only base outs at first, everything else you'd have to be pelted while running. Fun as hell. Girls always lost the game for you.