i was about to recommend toribash, but then i realized what forum i'm on.
sorry.

Iji was a pretty good platformer as well as cavestory, if you didn't try those then you should.

Cavestory was amazing. Beat it on hell mode.
before.

Ill check out iji

Who said anything about enjoyment? Try Penumbra, or Amnesia.

I'd also highly recomend The Orange box. TF2 alone is worth it's weight in hats. the half-lifes will give you 30 hours of solid gameplay. There are quite a few fun TF2 mods out there to toy with.

Garry's mod obviously.

I know this might seem like crazy but, have you considered not gaming? I mean, you are meant to have fun, but if you're not, try taking up another hobby. Try knitting socks.

Yeah, I play an instrument and compose while not gaming.

Penumbra scared the shit out of me before.

Great game.

When I get apathy I hit up acrade/casual games like
Bit Trip
Osmos
Plants vs Zombies

Suggesting some of my favourite games, also they are pretty cheap on Steam;
Zeno Clash
Mini Ninjas
The Path

Also I just play with friends, because ultimately gaming is fun because you play with fun people, in my opinion;
Diablo 2
Warcraft 3
Alien Swarm (Great because it is free so there is no excuse for not having it!)
Starcraft 2
Dawn of War 2

Warcraft 3 still have an active player base?

/me looks for battlechest

Of course dude.

Come play with me some time

I'm always up for some good old fashioned Warcraft.

Well gorman, i know one rpg wich is pretty awesome really.
I enjoyed it.

Recettear - An Item Shops Tale

Very special rpg, you are running a shop, goin to pay of some debts, get in dungeons etc, hard to explain game, but really worth it.

Yes,played trough the whole game co-op with 2 of my friends.Strongly recommend this,the most fun you will have in a while.