Black Ops stuff going on.
First of all, the latest DLC pack, Escalation, is now available for download on Steam at $14.99 -- four multiplayer maps and the celebrity-filled Call of the Dead are included. On top of that, Steam is offering a free multiplayer weekend, meaning anybody can download the game and sample its multiplayer side absolutely free, from right now until June 5 at 1pm PT. This weekend, all XP earned in multiplayer will also be doubled.
Finally, if you've found Black Ops to be to your liking, you can decide to pick it up at a reduced price this weekend: $40.19, 33% off its normal asking price.