Your RPG Museum

So Alexis has been talking about putting together a sort of database/museum/wiki/library of the best DIY D&D stuff--both in terms of rules and setting materials.

Not all the stuff, just the best stuff. So I'm wondering what such a resource would consist of.

My very simple request for today for y'all is:

"Give me a link to at least one on-line DIY RPG resources you have found to be useful in creating a game."

This should be, if possible, something that you actually used.

You are NOT allowed to link to any commercial product, to a novel, to any .pdf longer than 3 pages, or to anything I--or anyone else reading the comments--can't immediately read from the comfort of his or her home computer right now. You also can't link to anything you yourself wrote or to anything on this blog (though that's sweet and thanks if you were planning to), since I already know about everything on this blog.

This list helped me write up a random book table--which, yeah, I use, since snakes are books, and also I liked the throwaway rule about how owning a book on a subject helps with knowledge checks on that subject.

Also:
Noisms 25 word description of his Yoon-Suin setting: Tibet, yak ghosts, ogre magi, mangroves, Nepal, Arabian Nights, Sorcery!, Bengal, invertebrates, topaz, squid men, slug people, opiates, slavery, human sacrifice, dark gods, malaise, magic.

Always seems to me a marvel of precision and concision, and has helped me think about what different places in my campaign should be like.

Oh, and P.S...
it's Wednesday...