KotOR took a ton of my life away.
Starcraft/Brood war once I figured out how to make good maps.
Dark Age of Camelot (my first MMO. Played from dusk til dawn once. Ugh)
Skyrim took a toll on me recently, but I was actually on doctor's orders to rest up my broken knee.
Freedom Fighters from the original Xbox still calls me back at least every 6 months or so.
Halo, Morrowind, and Dynasty Warriors 4 (lol don't judge) stole an entire summer from me in high school. Yeaaah, no getting laid back then haha.