Need games to play for a loooooong time.

What about strategy games with an endless mode like Civilization or Anno?

Terraria (or perhaps Starbound would be a better suggestion now)
any popular MOBA if you think you may like those
if you like strategy games there are many time sinks in that genre, EU4 is the new craze, CK2 and Civ4/5 are good time wasters as well
quite a others...path of exile, warframe, rift (or some other MMO), dungeon defenders

unless you need games that you already own (just listing these off the top of my head)

Did you try any F2P game? There are some really fun time wasters there

Try to complete all Morrowind quests.

8 player Twilight Imperial with all expansions and remove imperial strategy card

age of wonders 3,
divinity: original sin,
eador,
lichdom: battlemage,
plague inc: evolved,
saints row IV,
warlock

Counter Strike Global Offensive :D I have over 2000h ^^

There is this one Skyrim mod I'd been keeping an eye out. But idk when it'll be released.

The Witcher, Mount and Blade Warband

Try sport games or arena shooters.

witcher 1/2 both about 30-40 hours for single playthrough, dragon age origins ~40, torchlight 2 about 20 hours without mods, sacred 1/2 both are pretty long, cant remember exactly because it was long time ago.
If you are going to try civ 5 again, much easier to start without the addons first. You could also try some multiplayer games mobas, mmos (Rift, Archeage, Tera(only the NA version) are decent without paying)

Strategy Games like Crusader Kings 1 and 2, Total War Games.

Talking about the Total War, i have literally spent months on the games of the series (Since Rome to Shogun 2). Dozens of different factions, dozens of different ways to play a faction and hundreds of mods.

As of CK, i own CK2 on Steam and CK1 out of Steam. On Ck2 i have spent at least 100 hours due to its unlimited kingdoms and on CK1 at least 2 weeks.

Binding of Isaac - I spent more time on it than on any big RPG.

Path of Exile (f2p), Inigo for Skyrim is amazing (and 2.0 just came out last month), if you can get into strategy titles you might like the Total War series-i see ppl put loads of hours into those games, or Rise of Nations (although the graphics are a bit dated even for a strategy title-its an old game but one of my all-time favs, i think i put 20 hours into the demo even before it came out way back when.)

Well you could always try the X3 series? They are a huge open sandbox game.

• X3 Terran Conflict
• X3 Albion Prelude
• X3 Reunion

The Mount and Blade series is also great, like Silverio suggested.

Darksiders, and maybe Darksiders II (which in my opinion is pretty long, it was too long for me :P (but played it through tho)). Heroesofmightandmagic III, Heroesofmightandmagic V (these are turn based strategy games, pretty good they are give them a try at least)

Dota 2?
Transformice?

7 days to die < Kinda minecraft style but better with zombies

Arma 3

Insurgency?

Grand theft auto 4

Just get Fallout NV,and play it atleast until you hit the strip.After that you will eather want to replay it 3 more times or will leave it forever.Also you can try Kingdoms of Amalur if you are looking for an RPG.

If you want a challenge you can try The Binding of Isaac. Easy to grasp, easy to play, very difficult to complete. Either you'll love it or leave it after a few minutes

did you just called torrent games demo ??

Dead Island, Bioshock, Civ, Borderlands :)

5 games I have that I've spent a long time on:

• Kerbal Space Program (probably around 1000h, I don't have it on Steam)
• Prison Architect
• Rimworld
• Sid Meier's Civilization V
• Spore

You're welcome.

EDIT: You pirate games? Ok, you're not actually welcome 'til you stop. Pirating music, I'm lenient, but games? That's too far.