String games were so much fun when I was a kid. I think it has become a dying art form. For Christmas, I plan to get both of my boys a set of strings. I know I could just use yarn, but honestly my boys are rough. I would rather spend a bit and save in the long run... not only on money, but my sanity as well.
I have found some great resources for string games while searching around. Hope you find some of them useful.
Alphabetical Listing of String Figures: how to instructions
String Games by Richard Darsie
String Games by Anne Johnson: comes with book and string
Kluntz: online seller of strings
Bella Luna: online seller of strings