Should stack with their Indie Weekend Sale, which I believe ends on Monday. Prices listed below are before the coupon code.
Torchlight = $3.75
Dungeon Defenders = $2.99 (Steamworks)
Space Pirates and Zombies = $2.49
Symphony = $4.99
Osmos = $2.49
Gratuitous Space Battles = $7.49
Terrorhedron 3D = $2.49
Nuclear Dawn = $8.99 (Steamworks)
The coupon code also works on pre-orders. For example Far Cry 3 would be $39.99 after the coupon.