It's difficult with Chinese boys around 7-13 sorta ages because they will get very engaged in throwing games or activity games and then start becoming insane and punching in the balls and throwing violently at innocent people etc.

One simple game/exercise that has had great success is putting words or sentences on the whiteboard and then letting them take turns throwing a soft ball or 'sticky ball' at the board.

You can add a point system.

Again, they seem to get super-engaged most times BUT they will quickly start throwing the ball at each others heads or the foreign teachers balls ASAP if they aren't strictly monitored and controlled.

Thats just one I could think about. If they hit a target and get it right they get to throw a 2nd or 3rd time. that kind of thing.

(a very very awesome version if you can find a toy gun that shoots a foam or sticky thing. but again if its a gun they get REALLY freaked and go into gun roid rages QUICKLY!)