I posted this awhile back.
If you go to a Claire's Boutique in the mall - they have these plastic inserts that you would put into a wallet PLUS they have a fold over top that keeps them pretty much enclosed; they are the exact size for the passes. They come in some very cool colors and you can put your passes in there, as well as, room card, credit card, etc. They are 3/$1.00 - I buy them every year and we go on all the rides, including the water ones, and our passes have never gotten wet. They keep them at the counter, so ask for them if you don't see them!
Hope this helps!