DAT ♥♥♥♥ AIN'T FREE!
It's a mod.

On the other hand, soldat was epic, even though my online never worked.

Browser based, it would have to be Eternal Red. No tower defence game has ever held my attention for over 3 hours until I played this thing. But as far as downloadable, I'd say Combat Arms, with Operation 7 in the same genre as a close second. (They may look the same, but trust me they're not.)

Gasp! Free online mods aren't free online games? Sorry, didn't know.

The mod is, but the games are still 20 euro's, so that's like saying that guildwars as opposed to WoW is free.(You still have to buy something.

And yes I know everyone owns a source game......

NEO Online is working pretty well for me now.
It's got really nice crafting.
And there are no classes, you progress as you want to.

Entropia Universe chould be fun, if the community was not aristocratic, with no starting cash, no NPCS to buy junk, the only source of starting cash = milking animals that look like dinos.

But you can withdraw in game cash into real life cash.

Be warned though the game works best if its got a initial investment. For example some dude payed $26.5k to buy a island ingame.

He remade his investment within a year by selling virtual houses and rights to hunt and mine. Mining while guarded by assualt bots.

tl'dr: Dont play Entropa Universe IF you dont invest anything.

Entropia Universe sounds interesting, but I am sure starting out there would be like going to a new country with no cash. So basically you would be a slave/migrant worker haha

Free Steam game right here http://forums.steampowered.com/forums/showthread.php?t=851573
Called TrackMania Nations Forever. Great racing game, did some nasty stunts in it and it has controller-enabled stuff, which I am fond of.

Played it for a couple hours, I have around 50 medals already. Acrobatics based levels are insanely hard to get Gold Medals for, but they are really fun.

I love Track Mania!
I even downloaded some modded cars!
I had the arwing from starfox! haha It didn't actually fly, but it was still badass

I am noticing a distinct lack of Alien Swarm.

It's good, but as pillbox said, it's kind of a week thing.
It's what happens when you don't have any new maps or campaigns or weapon additions.

Yeah, I'll definitely admit that. I really hope that someone actually makes some stuff for it eventually. It's pretty fun while it lasts though, definitely.

It's not out yet, but Vindictus is looking pretty sexy for a Nexon game.

Of course but if you manage a initial investment into the game, you chould probebly do good as a miner or soldier.

Or weapons dealer.

Do you mean online like in web? Or what?
If it's web, then it's Happywheels
If it's not, then it's Soldat!