What is the longest videogame you've ever played?

Either World of Warcraft or the main Pokemon games.

With WoW, I've played for over 7 years, playing off and on, and probably have clocked in over 1400 hours.

With Pokemon, I've been playing since yellow, and each generation earned 150+ hours.

For me, probably TLoZ Skyward sword with about 50 hours. I don't really play that many long games though.

Gesrs of war 3 18 hours for me

Assasins creed 4: Blackflag

Mass Effect. + Borderlands.

GTA IV. The credits alone are like 2 hours

In terms of multiplayer, it would be battlefield, in terms of story and solo games, it would be Borderlands

On Console: GTA IV was the longest campaign and online I've played. Yes, the campaign is longer than GTA V.
On PC: Minecraft. I may not like it, but hey, there are endless combinations of things you can do on it.
On iOS: Games like Simpsons: Tapped Out, or Clash Of Clans seem to provide hours upon hours of entertainment. I truly believe that in-app-purchases can lengthen those games even more.

I would say SecondLife… Its been 7 years and I'm still playing it…