I made one before I realized that you had deleted your request. Maybe someone else can use it...
It is in my 4shared file in the link in my signature. Then look in the "blank invitations" file. This would be a cute invite if you are having it in your backyard (or at a pool). You could have water games like slip n slide, sponge toss, etc. around the yard to give it a feel of a "water park".