I am bored, recommend me some FREE games to kill time.

are text-based games OK? I've tried Fallen London once, played it for few hours only, but it seemed pretty interesting.

I love tps, my favorite are gotham city imposteur, battlefield heroes, tribe ascend, loadout, ghost recon phantom, blacklight retribution, microvolt surge, also hawken, war thunder, warframe

Republia Times
http://dukope.com/play.php?g=trt

50 Best Free PC Games List here
http://www.pcgamer.com/uk/2013/09/21/the-50-best-free-pc-games/

Dead frontier

Dwarf Fortress

Marvel Heroes 2015

Defiance

I just found out about Catan Online, which I guess has been around forever. Awesome board game, hoping the online version is as fun.

EDIT: Well apparently my cousin lied to me, the base game isn't even free :-(

http://andrewmorrish.net/?page_id=313
http://www.crazymonkeygames.com/Boxhead-The-Zombie-Wars.html#game
http://www.kingdomofloathing.com
http://buildandshoot.com/play
http://www.bay12games.com/dwarves/
http://adarkroom.doublespeakgames.com/
http://www.twilightheroes.com/
http://www.classicdosgames.com/online/jetpk_ch.html
http://maplestory.nexon.net/
http://www.runescape.com/
there are more and probably better, but this is off the top of my head.
(also i haven't played them all in awhile, just remembered and googled so hopefully they're all up)

GunGirl 2 is a metroidvania, a great choice if you don't care for graphics.
ROM CHECK FAIL is kind of like Wario Ware Inc. in case you're interested.
The Mardek RPG or Epic Battle Fantasy series in Kongregate if you're into RPGs and Flash games.
List of Freeware games (TvTropes link, try not to waste 6 hours in a row on this website.)

For MMORPG you have Maple Story and for shooter, Combat Arms. Both free and online multiplayer. Cheers :)

Have you tried Contract Wars? (Shooter)

I can give a huge list of free games I've played. Mostly online multiplayer.

Some that I found good or decent (some already listed above) in no particular order include:

• Enigmata: Stellar War - (Unique space tower defense)
• Contract Wars - (Unity browser FPS with over 60 guns and a variety of maps)
• Platform Racing 2 - (2D multiplayer platform racing, not sure if people still play this)
• CS Portable - (Unity FPS shooter originally similar to counterstrike)
• Dead Frontier - (Top-Down 3D MMO Zombie Survival Shooter)
• Shellshock Live 2 - (Online, Artillery style game)
• Runescape - (You should know this, mmorpg)
• Spiral Knights - (MMORPG, top-down, dungeon-style)
• Freefall Tournament - (Online 3rd person shooter with jetpacks)
• Red Crucible 2 - (Online FPS with land and air vehicles)
• Bloons Tower Defense - (Fun tower defense series)
• Planetside 2 - (MMOFPS with massive battles)
• Robocraft - (Build own robot and fight)
• Warframe - (3rd person space ninjas, MMO, co-op)
• War Thunder - (MMO, WWII planes and tanks with arcade and simulator)
  (basically the rest of top free to play games on steam and too many other games to be listed or they are barely played now)

Games I have my eye on:
-Archeage - (Gorgeous and massive open world mmorpg "sandpark" game that uses Cryengine 3)

And I must mention:
RIP the game Vorp and the company that made it and died. It was a fun space MOBA.
RIP Starfighter: Disputed Galaxy (Hopefully Starfighter: Infinity goes well).
RIP Pawngame and Pawn Tactics (though pawn Tactics is technically still up).
and RIP any games I have forgotten or forgotten the names so I can't suggest it. :(

Pirates Love Daisies

http://www.pirateslovedaisies.com/

looks like all of the F2P games on steam is already mentioned
how about Facebook Games ? Lol

Flies in

Here you go, OP.

Flies away.

League OF LEGENDS op ;d

I an really enjoying Unturned lastly. Such a Rust for poor. But fun.
No clicky for you :*.

After seeing this forum post: Clicky and a video...

I have to mention Space Engine here. lol

Bad Rats (Technically Free) :P

Don't know if anyone suggested it yet but Heroine's Quest: The Herald of Ragnarok is pretty good.

nosgoth - http://beta.nosgoth.com/register/new

alien swarm - coop free on steam

Happy Wars is pretty fun. Marvel Puzzle Quest if you like puzzles. If you already have Portal 2, Thinking with Time Machines is an interesting mod that pretty much changes the whole game.

Play Some Scarlet Blade pretty addicting

Marvel heroes 2015 if you like ARPG and Superheroes. You can get 99% of the items just playing without too many effort (you can buy it for real money if dont want wait, the 01% of itmes you cant get just playing are cosmetic (actually is just one atm)

So are you going to make a list of free games you have played? lol

Tales of Maj'Eyal

te4.org

Easily my favorite roguelike and it is 100% free, you can donate (or buy on steam) but that only unlocks 1 extra class and the ability to store a few items between games. Unlike most roguelikes it has a good UI/controls rather than hiding information and control only with keyboard this allows mouse. It also has an optional life system rather than one death game over and graphics rather than the traditional ASCII.

There are many classes, and some races, to unlock along with a few extra skill trees for some classes and there is alot of variety between them. In some ways it can get repetitive, since the main dungeons are static, I still played through it many times just due to enjoying the different classes and often dieing before beat it. My personal favorite class is Alchemist followed by Necromancer.

It is also built with modding in mind as a roguelike engine others can freely use for their own games.