Today is the last day of the Indie Underdog Pack. (Try the 8-Bit Funding page if the main site is slow.) Some developers gathered to sell their old games in order to help crowdfund new ones. Honestly, they appear to be far from their goal at the moment. However, the bundle reward is immediate so you don't have to worry about not getting your loot. You can get 6 DRM-free games for a dollar.
I bought mainly for Koya Rift. It's sort of a procedurally generated, sidescrolling shooter with a dash of base defense. I've also heard good things about Infernal Edge (which is included in The Best Of Lazy Brain).