So Corpse Party is a PSP exclusive title only available on PSN for download. Unfortunately, I don't think it's available in Europe OR Australia (says Wikipedia), so I think an American would have to play it... so this might not end up working out but I still think it's worth a shot.
The game basically looks like a 16 bit RPG, but plays more like a puzzle game/adventure game. The story is based around some Japanese students who are saying farewell to a friend who is transferring to another school. In order to remember each other bye they say some sort of occult chant to be together forever <3 and of course, they fuck it up and get teleported to some... freaky ghost world/dimension?
There are a bunch of different chapters to the game, and you can play as different characters and you go deeper into the story and it seems like things might get pretty creepy and interesting. And despite the cutesy graphics style, from what I've seen, the game gets pretty gruesome and morbid at times.
Here you can basically see the opening scene and set up of the game, and a little bit of the game play.http://www.youtube.com/watch?v=N2SCtNwHOSU
It's a lot of dialogue and walking around, but there's a lot of different "endings" to the chapters. Based on the decisions you make during the chapter, it could lead to a different ending. It might be a good opportunity to get the chat involved, and it might be fun to watch them all screw stuff up haha.
Anyway, it looks like a good game to me, and I think it'd make for an interesting stream.