Simply put, what game has made you frequently look at the clock and think 'Wow, I can't believe I just spent three hours (or however long it was) playing'? For me, it'd most likely be Minecraft, whittling away hours building my underground empire. Desktop Dungeons is the runner-up, as it has all the makings of a massive time-killer, but I haven't had it for very long so it hasn't proven itself yet.
So, what are your time-vampires of gaming? (Furthermore, you could also discuss why it's so compelling to you. For example, Minecraft for me is probably related to the sheer unleashed creativity of it all.)
EDIT: Canabalt and TF2 get honorable mentions; I've sunk over 350 hours into the latter and have played the former for hours on end, trying to beat my record and wishing for plate-glass windows to all go die horribly (If you've played the game, you know exactly what I'm talking about).
So, what are your time-vampires of gaming? (Furthermore, you could also discuss why it's so compelling to you. For example, Minecraft for me is probably related to the sheer unleashed creativity of it all.)
EDIT: Canabalt and TF2 get honorable mentions; I've sunk over 350 hours into the latter and have played the former for hours on end, trying to beat my record and wishing for plate-glass windows to all go die horribly (If you've played the game, you know exactly what I'm talking about).