In other Portal news, the now infamous credit theme, Still Alive, will be coming to a Rock Band owner near you soon. Unveiled at Valve's own GDC party, the title currently has no set release date. Jonathan Coulton was one of the headliners for the entertainment at Valve's party, with a number from the Harmonix crew invited as well. I'll let the this quote explain the rest.
[W]e jumped on-stage and pulled out our Rock Band equipment piece by piece.[...] When they got to the song list they scrolled through an almost infinite amount of DLC until eventually they stopped on one- "Still Alive" by GLaDOSIt'd be nice if it was released for free. Hey, there's always hope!
Yup. That is the song that Jonathan wrote that is the credits song at the end of Portal. The crowd went nuts. Earlier we had turned the backing vocals all the way down and the microphone vocals all the way up so we could actually hear his voice instead of GLaDOS. Alex was on drums ruling it, and Dan Teasdale held his own on guitar. By the end of the song even the people in the back of the room were screaming. It was an awesome way to debut a song we've been working on.