Ah swiss balls, loads of fun....and make plenty of room just in case you crash. Playing catch on the swiss ball with a medicine ball is fun....in front or side to side. Once you master the kneeling then you go to standing.
Easiest thing to do is just get on one....and throw your weight around and counter balance....like riding a bull.
Note that the more pumped up with air....the harder it gets....and I learned that lesson long ago trying to jump on one....after someone had already pumped it up overnight and didn't tell me....let's just say I almost went through the ceiling.