What game have you played most (in hours)?

TF2 - 4,991
CS:GO - 1, 065
TheHunter - 261

my current top 3 on steam

On Steam...Terarria with nearly 350. Off Steam? Final Fantasy X for PS2 with over 3000 on a single save file. I still have the memory card with that save on it and it still works!

Team Fortress 2 -504
Call of Duty: Modern Warfare 2 - Multiplayer-260
Killing Floor-206

Garry's Mod - 1,602
Arma 2: OA - 1,267

Left 4 Dead 2, 388 hours

Unrecorded but I'm sure it is: LIttle Big Planet 2 - I invested hundreds of hours into that game :)
Recorded: Garry's Mod - 317 hours (like 1/3 of the time it was just running in the background I would say)

Well on all platforms the list would be:
Monster Hunter
Demon's Souls
Dark Souls
Dark Souls II

On Steam only:
Dark Souls II
Dark Souls

Judging form the list you could say I like to punish myself a bit.....

Apparently I have 794 hours in Civ5. Which is bad, but even worse I only have 73% of achievements...

On Steam, Terraria, with 111 hours.

The game I've played the most is probably Final Fantasy VIII. Beat it twice and currently going for a third playthrough.

My confirmed longest is probably World of Tanks with 2000+ hours, I was pretty active there 2010-2013, but I probably played Ace Online (2006-2010) and Operation Flashpoint (2002-2005) longer though I don't have any means to check if it's true.

Okay, now i don't feel like im playing too much video games, thanks guys :D

Diablo III + RoS 3000+ hours

Team Fortress 2 with 900 hours!

International Snooker 261 hrs
Not a outstanding game, poor graphic but physics system is just fine, besides I don't have any other choice.
If Pool Nation got snooker mode I'll change to that one.

On my steam account it says Skyrim is my most played game with 136 hours on record, more than any three of my other games put together. The strange thing is, I don't play Skyrim, my sister uses my account to play it...

The game I have personally played the most, it would have to be Unreal Tournament 2004. I have 32 hours on Steam and have probably played about 2000+ off Steam.

I have 5 hours on How Do You Do It. That's all that matters.

Borderlands 2 - 105 hours

War Thunder 370.2h (i'm surprised O.O)
Total War: SHOGUN 2 311.5h
DC Universe Online 215.7h (even more surprised!)

Garrys mod 285 h

Mabinogi Too many hours

1. 7 Days to Die - 275 Hours
2. Fallout New Vegas - 167 Hours
3. Skyrim - 128 Hours

Everquest.

Hours: Unknown, somewhere in the range of several thousand.

Torchlight 2 - 210 hrs.

Dota 2 - 2510 hours
PAYDAY 2 - 268 hrs
Counter-Strike: Global Offensive -86 hrs on record