For "waterproof paper," go to FedEx facility, pick up some of their large (free) mailing envelopes (Tyvek-like material). Cut the non-printed areas into small sheets. Maybe not Rite-in-the-Rain, but hey, it's free.

Oh, BTW, I'll PM my address if you'll put me on your Christmas list. <img src="/images/graemlins/grin.gif" alt="" />
_________________________
"Things that have never happened before happen all the time." — Scott Sagan, The Limits of Safety