The addicting games for me would be:

Zelda games, pretty much any of the Final Fantasies, most of the 8 and 16 bit games, Modern Warfare 2 online, Ninja Gaiden Sigma 1 and 2, just about all the Kingdom Hearts games, Fire Emblem, Megaman 64/Legends, Beetle Adventure Racing, Super Mario 64, Super Mario Sunshine, Burnout's crash mode and thats about as much as I can think of.