My thanks to the Make magazine blog for the nice mention in their article on aging the pages of a forbidden tome. It's a great write-up that focuses on a technique using ammonium chloride and a heat gun to char paper.
If you're a Maker coming here from the link you might want to try creating a "thing in a bottle", whipping up a Lovecraftian tentacle, or go totally over the edge and recreate the Dyer materials from Lovecraft's "At the Mountains of Madness". That last one proves that even the most geeky and obscure thing in the universe will have a fan somewhere on the internet. Heh.
Oh, and be sure to pay Curious Goods and Dave Lowe Design a visit. They're both just chockablock full of projects.