Terraria is 75% off today ($2.50), in celebration of the 1.1 patch being released (the first new update in six months). I've mentioned this game before, it's basically a 2D Minecraft crossed with Metroid and Castlevania. I have logged more hours playing it than I care to admit (my Steam friends can attest to this. If I could, I'd buy it again and get a four pack so I could force it upon my friends.