If you've never played the most excellent game Psychonauts before, I just thought I'd drop a heads up that the PC version is currently only $3.99 through Amazon right now. The short version of the plot is that you play as a young psychic who's run away from home to sneak into a summer camp where psychic children are taught to use their powers, and once he's caught he only has until his dad comes to pick him up to learn as much as he can. Most of the levels take place inside the minds of the various counselors and other people, and can get incredibly inventive since any kind of realism can be gleefully thrown aside for anything within the bounds of what the character who's mind you're exploring might have imagined up. Also, it's very funny and has some awesome characters. And it rewards you for dawdling around instead of going straight to your next task with little character moments building up the lesser NPCs so they feel more like full characters in their own rights.
This is my favorite game in the world, so I definitely recommend giving it a shot if you've never touched it before! How much do I love it? When I saw that it had gone up on Steam I bought it, even though I didn't know if my computer could run it, just because I wanted Double-Fine to have that money for making a game I loved so much. Then this year when I finally got a 360 and (even later) a wireless adapter for it I paid for it again through them, even though I obviously already have a console version, for the exact same reason. So, yeah, when it comes to Psychonauts I basically love it so much that I turn into this. (As do a lot of other people, considering the number of folks who seemed to pledge to their Kickstarter hoping that maybe, somehow, that'd lead to a sequel someday.)
Just to share, this is the story about the game that first convinced me that it had to be something special and made me buy it years back: the backstory for one of that characters is that she used to work in an orphanage, until one day it caught on fire and the children, and presumably the rest of the staff, were all killed (this seems like it should be a major spoiler but it actually isn't at all). When the game was being developed the level inside her head was originally supposed to involve the other campers in there with you getting snatched up by nightmares caused by that trauma, with you ultimately tracking them down and defeating them to free the other kids.
Then they looked at it and realized "Wait, we can't do this. With this character being who she is there's no way she'd ever allow children into her mind if they'd be in any danger" and the level and its plot were reworked into one where, while there are a couple of enemies, all the monsters are either in incredibly out-of-the-way areas, only show up once you've left an area, or are in spots that you pass though so quickly that you'll barely see them spawning before you're through and most of them will just stand there staring at you if you do hunt them down so you'll only be injured if you let yourself get nicked by their idle animation.
How many other game developers can you name that you'd believe would rework a whole area into a combat-free zone just because of in-character concerns? It wasn't even like they made the change when they were in the early plotting stages; the nightmare creatures and their fights actually show up in a different mind just because they were already done and they didn't want to lose all that work.
To give you more of an idea if you might like it, here's the opening cutscene to give you a taste of it, and here's a fanmade trailer which has kind of ridiculously overwrought music for a humor game but doesn't spoil the plot like the official trailer I found does. And, just for fun, Inceptionauts.