Double Fine's Costume Quest suddenly arrives on Steam

CostumeQuest

Unless you come from Sadlandia - a fictional country that's outlawed Halloween and kittens - you probably went trick-or-treating back in the days of your youth. But now you've grown older and hairier, and begging strangers for candy may as well be asking for a chocolate, nougat-filled restraining order.

Better still, you'll also nab the free Grubbins on Ice DLC pack. I'm not actually sure what a Grubbin is, but then, I didn't know what a Psychonaut or a Grim Fandango was either, and look how those turned out.