Yes, Left 4 Dead is awesome. I've played through the campaigns several times with friends. Through those sessions, it has provided me with some of the best multiplayer experiences of recent memory . Talk your friends into picking it up and have a great time. It's a co-op keeper (ie. don't rent, run out and buy it).
When I haven't been taking on the Zombie horde, I have been working on the complete rewrite of the 1337pwn.com XBOX Live Friends application. The new design gives the application a complete facelift coupled with totally new server-side code. We're currently on track for a December release. Yes, that's just a week or so away.
What's new? For now, let's just say that the update that has generated expletive-laced proclamations by anyone who's seen it. As we get closer to AppStore submission, we will post some screenshots and video. It's frickin' cool.
Thank you and...
don't pwn alone(tm)