It's the Distributed Proofreaders site, which allows everyone and anyone to proofread scanned text for Project Gutenberg's e-books. It's really cool. The rules aren't that hard to remember, and it's been really soothing, for me, to just be able to read a page or five of a book and quit with good conscience, instead of plowing through all of it in mere hours. The best part is getting notified when the book will be 'done' and getting to read it through afterwards.
For a relatively new mom that nearly never gets to sit down and read, it's a great way to read a little and feel good about it, too. It also helps to know that at least two someone elses are going to check my work, too, so that whatever mistakes I do make will be caught.