Well, HL2 Deathmatch is out, for those who have gotten sick of the Counter-Strike: Source multiplayer component.
Its a pretty good experience thus far but, from looking at it, I just don't understand why it was delayed at the retail sale since there isn't much to look at, really. Anyways, it's a real blast flinging debris and office furniture with the grav-gun and the physics really shines as you're tossing trash, bouncing back random projectings, and flinging back grenades.
Oh yeah, Steam is also allowing map downloads from the servers now (rather than disconnecting you). There's a few custom maps floating around for both Counter-Strike: Source and HL2 Deathmatch which should give you a little more variety.