Guitar Hero III had a hold of me for a while, I got that game along with Umbrella Chronicles and BWii... the two latter games have yet to be beaten (BWii has yet to be played...)

Fire Emblem: Radiant Dawn had me in a strangle hold until I beat it (3 days, 1 weekend, pure sweetness)

Melee and Brawl are obvious. Ever since FE came out, Brawl has been in. (Reason: I have no money for Mario Kart or Boom Blox)

Pokemon Diamond: This was the first game in which I finally understood how EV's and IV's work... so I trained my team with that method... and it took a very long time...

Sonic & Knuckles: before I owned the game I rented it every weekend and I played through it religiously. My parents finally wizened up and bought me the game.

Warcraft III: I still play that game to this day (Custom Games ftw) Mauls are still a Smeags favorite, although everyone plays DotA now-a-days...

i have been addicted to several games
pokemon blue
jet force gemini
SSB
SSBM
SSBB
Phantasy star online episode 1&2 (GC)
final fantasy X

the list goes on and on, i can think of a lot more games i just dont feel like typing them all.

Back in the day it was Square games.

As of recent, Blizzard made games have done it to me. Diablo,Starcraft, Daiblo 2 and Warcraft 3.

Blizzard=Quality.

the first game that i was addicted to was Pokemon on the gamboy. I had both red and blue and i spent about 100 hours on both of them. i even remember taking my gameboy to school and playing it in the back of the classroom. currently i can't stop playing cod4 online but i think thats my friends fault because they always want to play online with me.

How could I forget about Pokemon Red? When all of my continuating fifth grade class was saying their goodbyes and signing yearbooks, I was trading Pokemon with my friends.

I also got addicted to the first Roller Coaster Tycoon and The Sims. Especially Roller Coaster Tycoon. I'm no good at RCT3 though.

Pokemon Red: I daydreamed in class trying to think of how to wake up the Snorlax--then it hit me Use the Flute I couldn't wait to get home; then KOTOR I was determined to "Rule the galaxy HA HA HA"

COD4 online.
I had to sell the game to stop playing it so much.

Wolfenstein Enemy Territory

So many years playing it with so many weekends just devoted to it.

Meteos. A whole summer of playing it and closing my eyes and still seeing the pieces fall.

Civilization 1, 2 and 3
RE: 4 - I've beaten the gamecube version so many times and the Wii version a couple
SSBM - My play count is ridiculous
Mario Kart Wii - my race count is over 1000