What is the SCP Foundation?

I first heard about the SCP Foundation when someone reblogged it on Tumblr and it scrolled past on my dash. After looking it up at Know Your Meme, I was smitten.

The SCP Foundation's mission is "Secure, Contain, Protect." It is basically a work of collaborative fiction, a collection of creepy stories in a government report format. Sort of like an X-Files that everyone can update. It makes for great browsing, but maybe not late at night!

Image courtesy Flickr/hball