Fortunately, Ticia at Adventures in Mommydom just posted a great tip of putting the balloons in a pool to keep the ones on the bottom from popping. I normally don't make that many balloons in one sitting, however, you can see I did this time!
I almost forgot we had this fun little toy in our pool bin. I picked it up last year on the big Target clearance sale and it really is pretty fun. It's like playing hot potato with a water balloon. Of course, my kids want to be the one holding it when it pops. Fun!