Amazon has really outdone itself this time around...
The Microsoft 5-Game Arcade Pack just hit Amazon a couple days ago, and it's now on sale for a mere $10 until Feb 2nd. It includes the following:
Mark of the Ninja
Insanely Twisted Shadow Planet
You'll get individual Steam keys for each game. If you're only interested in one or two of the games, each individual title is on sale for $3.75 apiece, except Toy Soldiers at just $2.49.
Since I did not own any of these games and have been waiting for a good deal for Deadlight and Mark of the Ninja, I snatched up whole pack. Heard good things about all the games. In fact, every single game has a metacritic score of 70 or above.
EDIT: Also, I should point out that if you still have one of those $5 Off EC coupons, they apparently work for this.