It's been a while since I played a PS2, but I still remember these games that made me play all day.
-Metal Gear Solid 3 subsistence (Felt like I watch a very good movie)
-SmackDown vs Raw 2006 (I remember unlocking everything, took me a lot of time)
-Grand Theft Auto: San Andreas (It got me hook up, I had so much fun)
-Dragon Ball Z: Budokai Tenkaichi series (love the wide range of characters)
-Guitarhero 1 & 2 (Introduces me to very good music)