There's a lot of good deals over at
Steam right now. Several developer catalogs are up for ridiculously low prices, with individual game sales varying per day throughout the holiday. Some of it is the usual, but there are some newer games and lesser-known indie titles on there that I haven't seen up for sale before.
They're also posing game-specific challenges each day. Completing a challenge earns you a ticket, which can be redeemed for DLC. It also enters you into a chance to win your top 10 wishlist titles. Some of the challenges don't even require you to start up a game (link with Facebook, join a group, post to a friend's profile, etc). A few of the games even have Summertime specific updates running right now. Killing Floor enabled a massive themed facelift in a similar tone to their previous Christmas update. I have my steampunk Mr. Foster... do you?

Definitely some cool stuff going on right now.