So almost my entire office is having a blast playing with Google Wave. The closest I can come to describing it is that it's IM on steroids and speed. It has the potential to be a great collaboration tool (or possibly time waster...) It really is a lot of fun getting to know my way around. It's still in testing so it's not perfect yet and it's not available without an invite.
That said, I have 6 invites left for this thing. If anyone wants an invite to Google Wave let me know. I'm willing to give away at least 4 of the invites here to whoever asks first. Just leave me a comment with your Gmail address and I'll get it sent to you.
Update: I actually now have 22 invites left. Let me know if you want one! :)