I was at an Outdoor store called Outdoors Oriented in St. Catherines ON and remember seeing a little deck of cards of knots. It was shrink wrapped and I did not pick it up to look at it but I suspect that they might be water resistant. Keep an eye out in the impulse buy section of any outdoor stores you frequent.
I think there maybe only a handful of knots that could get you through most things. Take a look at the above links, get some rope and have fun. I find doing knots almost therapeutic at times and the constant repetition in tying them and untying them makes them second nature. If I lose hardware then I can still get by. As the Dual Survivors say, the more you know the less you need.