Portal is only available on PS3 in The Orange Box, which comes with 4 other games (all made by Valve, developer of Portal 2): Half-Life 2, Half-Life 2: Episode One, Half-Life 2: Episode Two and Team Fortress 2. I have The Orange Box for PS3, I got it for about $20 (used).
All of those games are amazing, and all of them are in my top 20 games of all time. The Half-Life series are first person shooters, but they're not at all like Call of Duty (they're 100x better). HL2 is about 10-15 hours in length, whereas HL2: Episode 1 is about half that, and HL2: Episode 2 is about 7 hours. Portal is really short (about 2-3 hours), but it's excellent.
Portal is basically Portal 2, but without Wheatley, Cave Johnson, Mobility Gels, Discouragement Beams, Excursion Tunnels, Aerial Faith Plates and a much less epic story. Don't get me wrong, though, it's really, really good.
Team Fortress 2 is purely online multiplayer. It's an FPS, but also not at all like CoD. You must choose your class, which are: Demolition, Scout, Spy, Medic, Heavy, Pyro, Soldier, Engineer and Sniper. Each has their own unique weapons and special abilities (i.e. the spy can temporarily become invisible and the heavy can take more damage). TF2 is a TON of fun, and there's still quite a bit of people playing it. It's much harder to get a kill than in CoD (or most other FPSes, for that matter), and there's definitely a learning curve, but once you're good it's just really, really fun.
So, The Orange Box is 5 incredible games for $20-$40 that'll last you about 30 hours (infinite hours if you like TF2). It's been described by many as the greatest deal in gaming, and for good reason.
Anyway, hope that helped. I really recommend getting The Orange Box. While Portal only lasts a couple hours, you'll replay it many, many times (I'm on my 10th replay).