HELP ME DECIDE ON A GAME!

[Chojin]

I'm trying to get Emily into some traditional gaming as most of the titles she's familiar with are either rhythm-oriented, MMOs, or exclusive to the Atari 2600. I'm trying to get her into games that involve 2 or more players cooperatively, but are mainstream genres and not overly kiddy. This is because I would beat her in versus games, I'm trying to get her foot in the door to gaming in general, and she'd instantly latch onto kiddy games and never stop playing them. And the only problem with that is that most people don't do that shit :<

Basically, I'm looking for some sort of cooperative 2+ player adventure/platformer for XBox that does not require a lot of deep thought to operate. Simple cooperative maneuvers would be appreciated (like how you can do tandem attacks in Simpsons arcade by holding the buttons when near each other). Something that is cool and sadistically humorous would be preferable to something HARDCORE BLOOD GORE HAHA OWNED would be great.

I'm also in the market for a SIMPLE FPS to get her into for PC. Right now I think the best one I've got is the new Unreal Tournament, but something where she can't constantly fall to her death by accident would be great, too.

Adventure/Platformer/Sidescrollers I'm considering! PLEASE REVIEW!
Blinx 2
LOTR 2 & 3
Mortal Kombat: Shaolin Monks
The Incredibles: Rise of the Underminer
X-Men Legends 1 & 2
Dynasty Warriors 4 & 5
Metal Slug 3/4/5
Lego Star Wars
Godzilla: Destroy All Monsters Melee
Phantasy Star 1 & 2
Baldur's Gate: DA 1 & 2
Hunter: The Reckoning Redeemer
Fallout: BOS (I thought this was the TBS game, but apparently there's a shooter by the same name?)
Dungeons and Dragons Heroes
Star Wars: Battlefront

FPSes I'm considering!
Doom 1/2 and Quake (Srsly)
Unreal Tournament 2K5 (or whatever the new one is)

Any reviews and thoughts would be appreciated! We're having some fun with Jet Set Radio Future's Ball Hog co-op mode, but it doesn't work too well against computer opponents.