Pastee
Pastee is yet another pastebin. I didn't like some of the design decisions of the popular pastebins, so in 2008, I started my own.
Pastee came to fruition during the Yahoo! Hack Day at UIUC in September 2008. It won the Best Overall award.
As of April 2009, it's still not open source. I haven't touched the code much since Hack Day. However, in the coming months, it will be made open and hosted on GitHub at msparks/pastee.
Until then, you can use the unfinished, slightly buggy live version at pastee.org.