I swear there was a thread that was discussing free to play games, but since I can't seem to find it now I'll just make my own! Perspective - This is a puzzle game that reminds me of portal simply because of it's creativity. Like portal, it only tells you the very basic controls, and then helps you learn the actual game mechanics through inuitive level design. The goal is to get a 2d character to the end of the level, but you manipulate the level by continually changing your 3d perspective of it. Starcraft 2 Arcade - SC2 just released a new content update that, among other things, made large parts of the game free to play. From my understanding you can play all custom maps, vs ai, and the entire arcade for free. What you don't get access to is the competitive ladder and the campaign. You can even get some access to team ladder games by playing with someone who has a full copy of the game (google sc2 spawning if you want to look into that). Hearthstone - This is a new blizzard game that just went into open beta. It is an online collectible card game and is blizzard's first truly free to play game. It's is very simple and easy to learn, but there is no lack of depth to strategy. No idea if they've released it yet, but it will be supported on tablets even. While perspective is really only good for a single play though, the two blizzard games can be played indefinitely. SC2 is probably the most demanding in terms of system requirements, but running on low graphics will greatly help with frame rate for those with a weaker machine.
I've been playing Tera Rising (mmorpg). It's a big download (25gig), but a very pretty game. Unlike other F2P games, its not Pay2Win, with most things you could pay for are cosmetic things.
Oooo I wanna say things! (Most links are to download pages but none start the download automatically) Tribes: Ascend - A high-speed, team-based FPS mostly focused on the Capture The Flag game mode. A little buggy and a little poorly balanced in places but still playable. Requires a more modern computer. The company behind the game abandoned the project a while ago, so no new updates or weapons until they release the game for coders. I think the game is fun but it has an amazingly high skill ceiling for an FPS and many people call it "pay to win" because it's hard to start out playing and you will die a ton. I've been playing regularly for two years so it can be played for a while. Legions: Overdrive - A game in many ways like Tribes: Ascend but was released for modders after it was abandoned in 2008, so it still gets updates, is balanced, and has a sort of small community but there are usually at least one or two servers open to play. I haven't played this much but will when people stop playing Tribes. Will run on a potato. Quake Live - Play this if you like arena FPS (i.e. Unreal Tournament, Quake) and think you're good It has been abandoned by all but the best players so it's a bit hard :c Will run on a potato. Catlateral Damage - Fun for a few minutes and not really developed, but you get to throw things off of shelves as a cat which is pretty fun for a while. Works on most computers. Octodad - Play as an octopus masquerading as a human father. Octodad is fairly challenging and the focus is on the tentacle controls, which may make one want to kill themselves. Works on most computers. Mechwarrior Online - Become a big stompy mech and smash other people's big stompy mechs. Requires a decent computer.
Planetside 2 - think halo, COD, and Far Cry wrapped into one package. Pretty much eternal warfare on a gigantic map. Totally pay to win, but still fun regardless. Team Fortress 2 - If you haven't heard of this game, you should probably go look it up right now. Also, hats.
Nice list nav. I initially thought you had a typo with catlateral damage... should have known better. I've heard a lot of good things about PS2, but never took the time to try it out. Bummer that it is pay to win, but hell what isn't these days? Going to have to give that one a try. Also if anyone does happen to try some blizzard games and wants to add me, feel free. ZMilla:948
Yeah, it's really graphically intensive for some reason. I have a pretty decent computer and I max out at around 45 in large firefights. Perhaps Far Cry wasn't the best analogy, I just meant that it's an open map instead of a small battlefield instance.