Cool games to play in the pool?

I have a pool that's about 5 feet deep. I need cool games for a 4 year old (we watch her very closely, she wears floats.), a 12 year old, and a 13 year old. We have tons of floats.|||Marco Polo a tag game "IT" must close eyes and when "it" yells "Marco" everyone else must yell POLO. Hours of fun for all.