Costume Quest!
From Tim Schafer's Double Fine studios, Costume Quest's budget may be low - but in terms of quality and style, it's through the roof! The game is basically a celebration of all the things that make Halloween great. You take control of a group of kids in cheesy home-made costumes as they go out trick-or-treating in their pleasant suburban neighborhood - only to discover that the place is overrun by monsters out to grab all the candy for themselves! To an eight-year-old kid, no greater atrocity can be imagined - and when the protagonist's twin sibling is kidnapped as well, this leaves your crew with no option but to fight back.
The cool part is that every time a battle starts, each kid transforms into whatever their costume is meant to be (attack robot, astronaut, Statue of Liberty etc.) and proceeds to kick ass like a boss! The battle system is a simplified version of the turn-based combat seen in classic Final Fantasy games, just complex enough that you'll lose the fight if you don't keep your A-game coming.
Oh yeah, and you get access to several new costumes as you go along, each with its own strengths and weaknesses - and often some kind of useful ability that may be used to open new paths outside of combat.
The game itself is kind of brief, but add the optional DLC-package 'Grubbins on Ice' and the recently released 'Costume Quest 2', and you're in for an epic that should keep you busy at least for a few days!
EDIT:
Ten Foot Bunny said:
Stacking is a whole lot of fun and it's got quite a few laughs to boot. It's one of the most original games I've played in a real long time.
I second this. Another one from Double Fine!
