Longest game you played

Approximately 3,300 hours played on World of Tanks. (Been playing it since 2010, however my activity has been all-time low now)

Steam...that'd be Football Manager 2013...~1,645 hours played.

Barbie dress-up game

Diablo 3 over 1000 hours, and Spellforce: Platinum Edition, 200+ hours on a single playthrough.

street fighter 4 and its installations...prolly over 3000 hours. apart from that 2000ish hours of dota 1-2 combined. aaaand fifa 99...i dont know how much time i spent on that game.

Absolutely... Skyrim! (2 hours) :D but Wolfentesin: Enemy Terriotry... i mean +1000 hours :) i play it several years

CS 1.6

199 logged hours in CoD: World at War, at least another 50 of not logged hours(offline mode) most of it multiplayer.
2nd is Terraria @ 102 hours

Minecraft, BF3, GTA Vice City, Street Fighter 2X

This one was pretty easy

The Longest Journey

Dota 2 with 3664 hours
Mw 2 with 1060 hours
Skyrim with 340 hours

I spend about 150 hours in borderlands 2, and i'm almost three quarters in the second playthrough and then there's still the third playthrough, so when i finish i'll prolly have spend 250-300 hours on the game.

4,700 hours, League of Legends
90 hours, Dark Souls 2 - one character

For me it's definitely FF X-2, I've played it for ~200h while using the guide for 100% finish (half of the time when I played without the guide, but missed a ton of content :P)

btw I gave up when I ended up with 99.5%

Guild Wars 1. Over 7K hours and that's not counting the time I played in the closed betas.

3000+ hours on Final Fantasy X. The save file timer stops at 99:59 xD
I'd played so much I had removed all the +2 stat nodes on the Sphere Grid and replaced them with +4 stat nodes.

5 years of Operation Flashpoint (99% singleplayer user-created missions)

4 years of Space Cowboy Online aka Ace Online aka Air Rivals

3 years of World of Tanks (around 3.000 hours)

Lol@people adding mmo-s on this list . Fallout , skyrim , oblivion , morrowind ,gothic 3 ,stalker , borderlands and few more .

6 years of WoW and 187 hours of FIFA 13.

50 hours save of Pokémon Diamond - never finished the game though - got bored of attempts to beat Cynthia. Why's she there anyways and why I have to beat all Four just to fight her again and again? T_T

Team Fortress 2 1,103 hrs on record

I am playing FF X HD atm :D Im not 20 hours in tho, but I know what I am getting into, I am enjoying it!

Nothing in particular, but many of the Spiderweb Software games clock in at 90+ hours of gameplay. Obviously not counting things like LoL, Dota2, and wc3 which each have at least 200 hours (for wc3 I probably have over 10k hours played, custom games ftw)

Quake Live, I don't know how much time I've spent on this game but I'm pretty sure it's 1000+, and it's coming to Steam. Oh yeah.

If you're talking about a single play-through of one game, that's gotta be one of the RPG's I've played. The first time I played through Dragon Age Origins, for example, it took me around 130 hours. I think Baldur's Gate II took around 210 hours to complete.

If you're talking about the most hours played in a single game, however, that's different. Diablo 2 tops all my other games in that respect. Been playing it since 1999 and still enjoy it.