I felt like making this thread after I noticed the amount of hours I've spent on Metal Gear Online. What video game have you spent the most time on? [and how much time?]

My answer:

Metal Gear Solid 4 at 2,048 hours [25 hours on MGS4 and 2,023 hours on MGO] [in Almost 3 years]. Keep in mind that in my case, MGO, keeps track of every second I'm on the game, including idle time. >___>

Halo...

^^^^^ 

Game, in general, Tetris.  Between the 20 different versions I've played I've spent a plain stupid amount of time playing that game.  I've spent more time than I even spent playing FFXI and I played that game for well more thna five years.  I've been playing Tetris for more than 20 years and loving every minute.  I can easily start playing for what I assume will be no more than 15 minutes and then all of a sudden it's three in the morning and five hours later.

If I don't count all the different versions of Tetris together, it's still probably Tetris.  Probably Tetris for the Game Boy (through the Game Boy itself and emulators) or Tetris DS.  I've spent a ridiculous amount of time on both.

sc2

Probably pokemon blue, I've played through it at least a dozen times and I expect at least a 800 hours playtime, if not 1000.

This gen I've broken the 200 hours mark on SSBBrawl and Pokemon Diamond

of all time maybe SOnic 2. my first video game and i still have a copy. Recently its been AC Brotherhood, ive spent 35 hours in SP mode and i have no idea about online. 

Metal Gear Solid 1

It's either Animal Crossing, Halo 3 (mostly for its multiplayer) or Oblivion.

Just checked my save file for Oblivion, I have played over 500 hours... XD yet, after all that time, I can still come across a place I haven't visited. 

I've never timed myself, but I'd have to say it's either Mass Effect 2, Panzer Dragoon Saga, or Halo Combat Evolved. ALl for different reasons.

I had to replay large portions of Mass Effect 2 trying different senarios trying to get both Maranda and Jack to be loyal and keep everyone alive in the end.

Panzer Dragoon Saga is my all time favorite RPG and I've replayed it more than any game. It's not the longest game if you just do the story, but it takes longer to get all extras and fully level up your Dragon.

Out of all the Halo games I've replayed the first the most. Plus I spend countless hours playing LAN with friends. I never really got into online play much so while I've played multiplayer in them all I think I've spent the most time playing the first.

Donkey Kong arcade may start ranking high on my top played list since I've been trying to get a respectible score on my arcade cabinet. I'll never beat Bill, Steve, or the Doc, but I would like to beat that little toad Brian Kuh.