Since I did promise her I'd recommend some PS2 games for her. I'm going to sort them into their ratings category since she is just a munchkin XD
Rated Everyone:
Harry Potter and the Chamber of Secrets: Even if you're not a Harry Potter fan this is still a fun (and easy) game to play. I think it was one of the first games for the PS2 since the load times take forever.
Spyro the Dragon: Enter the Dragonfly: Not quite as good as the original Spyro on the PS but still really, really fun. The graphics aren't quite as up to snub as you'd expect for the PS2 but it's easy to overlook that.
Spongebob Squarepants: Battle for Bikini Bottom: Even if you aren't a Spongebob fan this is one of the funest games I've ever played. The real actors do the voices which is a plus. You get to play as Spongebob, Patrick and Sandy. I so want to play this right now!
Nascar Thunder 2004: This is how I remember most of the drivers. Robbie Gordon as the 31 car. Junior as the 8 car. Mark Martin as the 6. Ah, fun times. Unless of course, you're like
dorkboyblake and have something against Nascar, there's always...
Gran Turismo 3: It's fun. I'm not a fan of it but it is fun.
NHL 2004: We'll just ignore the fact that this is the only NHL game I have for this system. It's hockey. Need I say more?
Rated Teen:
Final Fantasy X: One of the best games. EVER. The characters are awesome (except the whiney douche you play), especially Lulu. The graphics are phenomenal. The only drawback (or plus, depending on who you are) is this game is long. One of my original games has 40 hours invested in it, and I'm barely at the half way point. It's so worth the time invested in it. Just ask
zee014 . I got her addicted to this game. You won't regret buying this.
Tomb Raider: Legend: The best Tomb Raider game on the PS2. Angel of Darkness is dead to me! DEEEEEEEAAAAAAAAAAD!!! Be prepared to die though. A lot. Lara is such a fragile creature that one little slip on a rock surface will have you plummeting to your girly shrieking death.
Tomb Raider Anniversary: It's just the first game re-released with the new designer guys (Not Steven and Chris XD) doing the graphics and everything. It looks better, Lara is able to use her new grapple hook but there's no background music to keep you entertained.
Tony Hawk's Underground 2: Designing your own skateboarder is fun. If you suck at it like I do though it can take you forever to complete a level, and you'll just get bored of it. Once you get the hang of it though it's pretty fun. What's kind of annoying is Tony Hawk will even call your girl character "dude".
Buffy the Vampire Slayer: Chaos Bleeds: Fun! Not just because it's Buffy but it's a really fun game to play. The only actors who don't do their characters are Sarah Michelle Gellar, Alyson Hannigan, and Emma Caulfield. The woman who does Buffy actually does a good job sounding like her. You get to play as all the main Scoobies, including Spike and Faith. Kakistos is hard. Really, really hard.
Rated Mature: you do have to be 18 or over to buy these.
Resident Evil Code Veronica X: One of the longest RE games it's also one of the best. The RE team really went all out with the PS2's capabilities, the game looks and even sounds awesome. Many of the puzzles are still pointless time wasters but it's still fun to blow zombie brains out and screaming like a little girl when a zombie jumps out at you.
Tom Clancy's Rainbow Six: Lockdown: You don't need to be a fan of military stuff to like this game. Find the terrorist, shoot the terrorist. Try not to shoot the hostages. And try not to accidentally blow up your teammates with a grenade. Not like I know from personal experience or anything.
Silent Hill 4: The Room: Like the Resident Evil games, but with a slight religious twist. I'm not really into religion stuff myself but it is fun to shoot demon dogs from hell, and stop people you've tried to help die and come back as demons and try to kill you.
God of War: This game is hard. It looks really cool though, the graphics are right up there with FFX. It is super hard but it's still fun to play. You'll die a lot though. He dies easier and more often then Lara Croft.
Resident Evil 4: Ammo is easier to come by than in previous RE games the common cold so this one is slightly easier than previous RE titles. The RE team redid the controller system and enhanced the combat system. You can actually zoom in and shoot the zombies wherever. It's really fun to shoot them in the kneecaps and watch them slowly stagger towards you.
The Punisher: Yes, it's based on the comic hero, so yes it's incredibly violent. What kinda sucks though is they were told to censor some of the really, really violent scenes so they end up flashing to black and white then back to colour once the guy is dead.
I have a lot of other games too, but most of them I haven't actually played yet, so I didn't include them on here. Hope this was helpful!