I haven't played on a PS2 in years, but my friend has one and she's looking for some games. I did recommend the GTA series and katamari but my knowledge on any other decent games is slim, go forth and provide me with bountiful information (and a little idea of what it's about) for some games to suggest

twisted metal black....black was sick too for that matter.

oh, god of war.

Resident Evil 4

Final Fantasy X

Final Fantasy XII

God of War 1 & 2

Prince of Persia 1, 2, & 3

Star Wars Battlefront I & II

Destroy All Humans 1 & 2

Mercenaries

Metal Gear Solid 1, 2, & 3

Devil May Cry 1, 2, & 3

Baldur's Gate: Dark Alliance 1 & 2

Jak & Daxter, and Jak 2 & 3.

Jak X Combat Racing

Burnout Revenge

The Matrix: Path of Neo

Grand Theft Auto: San Andreas

Mortal Kombat: Armageddon

Well I ended up listing about 90% of the PS2 games I own lol, but those are all fun old games I used to enjoy. Too many to describe individually, so use Wikipedia.

Depends on who the games are for, what they're into. I'd highly recommend any of Pandemic's older stuff, including Mercenaries, Destroy All Humans and Star Wars Battlefront. They were an awesome company before EA ruined them. The Jak series is my favorite platformer series of all time, I used to love those back in the day. They may seem kiddy, but they do have some mature humor, at least after the first game. Metal Gear Solid is great, but definitely not for everyone, same with Devil May Cry.

Definitely Baldur's Gate. I think you'd love it, Avahra.

Totally agree with Baldur's Gate!! .. Tam and I used to stay up late at night playing that. There's a really good cheat for it too that lets you get tons of money and I think Dritz is a playable character in that game.

Don't pass up "Sly Cooper" or "Ratchet & Clank" either.

Fatal Frame 1-2 are good and really scary.

And the masterpieces in gaming "Ico" and "Shadow of the Colossus" .. these game even hold up to PS3/360 standards.