The latest IndieGameStand deal is for SpaceChem. Pay What You want for the game and you’ll get the DRM-free version. If you pay a minimum of $1 or more you’ll also get Steam, GOG (includes 63 Corvi DLC), and Desura activation keys.
The deal ends in about 2.5 days.
The best thing about this deal is probably the GOG key. Discounts usually only go up to 60% off unless it’s one of those buy 5+ game to get X% off deals.