Once again, Steam is running a huge seaonal sale. Normally, I'd be all over this, but as I'm still saving for a replacement car, I have to pass on it this time. However, don't let that discourage you! Here's some recommendations from the backlog and some other previous playing that you can get for cheap today. (Links go back to the backlog entries.)
Sanctum: $2.49 - This is my top recommendation from the whole lot for today. My buddy Aaron Stack and I have sunk many a gleeful hour into this, making unreasonably cruel tower defense mazes, coming up with silly names for the alien creeps and just generally having a blast. If you've got a spare $2.50 and like tower defense games and/or FPSes at all, this is a great purchase to make.
King Arthur Collection: $10.00 - Just because I haven't finished and reviewed this one doesn't mean I haven't been enjoying it thoroughly. A fantastic take on the Arturian mythology and a really fun game to boot.
Fallout: New Vegas: $10.00 - A great sandbox RPG from Bethesda that was worked on by a number of people on the original design team for Fallout 1 & 2.
Deus Ex: Human Revolution: $24.99 - Frankly, for as new and as high-quality as this game is, I'm amazed they're letting it go for so cheap, but whatever - if you don't have this yet and want to play it, this is as good an opportunity as any.