wish we had a pool! but maybe you guys do! So here's some inspiration to Frost your pool party!
Set up a color table with items you would find poolside or take along to the beach - cutouts of surf boards, beach umbrellas, buckets, noodles, etc. Source
Hang dollar store beach balls from the ceiling inside for a fun touch! Source
A great way to cool off... rent a snow cone machine! Setup up a flavor station! If you don't want to go through the trouble of renting, setup a freezer pop or icecream bar instead! Source
These rainbow donuts would be perfect "inner-tubes"!Source and recipe
Super genius cake pops! Turned into "beach balls" - these would be a great favor to serve! Source and tutorial