Yeah, most of you will probbly already have played at least half of what I have in this list, but I really think this should be stickied and added to with other member's recommendations, just to generally increase gamer awareness. It's these free games that pretty much weaned me off of being a Nintendo purist. Still love Nintendo and their quality, but now I've been able to find other games that capture that same level of quality, and in some cases even exceed it.

Online:

Warbears

Don't get fooled by the cute nature, these silly missions require a high level of thought and skill to figure out the order and timing to completing each level.

Seppukuties

Seriously, it's an awesome game, and it is possible to download, all you have to do is save the page. I'm currently supporting it with a ton of custom levels which you'll be able to see in that thread I showed you.

Nanaca Crash

Seriously addictive, penguin launch style game, but with much more control given to you. You only need one button; your left mouse click, but then it's ALLLLL about the timing, and some good old fashioned luck too.

GROW which is an excellent series of games. I've managed to complete most of them, but only gotten the best outcome on a few of them. Basically, each round you place one of the possible pieces into the area where they can grow, but sometimes one piece's growth is dependant on another's and sometimes one piece can get in another pieces way or kill it entirely. sometimes a piece can grow in multiple manners with different amounts of growth possible for each. Grow 2 and Grow RPG are my favorites of the series, but Grow 3, Grow Cube, and Grow Island are also quite fun(though for some reason Grow 3 doesn't like playing on my firefox, but it does work in IE, but that might just be me, it played in firefox fine before). There are a bunch of other games on the site as well, including Dwarf Complete which is a fun sorta puzzle, dungeon treasure hunt type game. Vanilla is another one of the games on the site that aI recommend, though it's utterly addicting in its simplicity, yet difficulty.

Download:

Cave Story

Free to download, an updated version'll be out on Wiiware eventually, but this version is still utterly incredible. simple yet smooth constrols, beautiful pixel art, fun characters, excellent plot, and even alternate endings

N

I didn't see the DS version in your list, but this game is seriously fun. The free PC game has 100 levels, each consisting of 5 stages. so you basically have 500 stages of varying difficulty(usually hard though) the controls are simple, but subtle, and difficult to master, but once you do it's an incredible game

Fl0w

Kinda cool relaxing game where you eat or be eaten, while going as deep as you can.

Within A Deep Forest

Another pixel graphic game with simple controls. I'd hardly put the art or storyline up on the level of cave story, but it is quite nice and relaxing to play, though frustrating in many cases. You control a ball, and must gain new materials to use in order to traverse the game and save the world.

Knytt

A simple scavenger hunt game with the same graphics as Within A Deep Forest but a little easier. There's also a "Knytt's Stories" game, but I haven't played that yet.

Cat Mario

A frustrating Mario type game that takes every pre-established mario convention and turns it totally on its head. This game is NOT fair, but it CAN be beaten.

De Blob is probably essentially the same as a demo version, since this seems to be from back when it was still an indy PC game by students. I would have mentioned it, but I really don't like the controls that much. I've heard a lot of other people love it though. It strikes me as having a flavor similar Katamari Dymacy, though with different game mechanics

Gametap - Gametap is a subcription based service that you have to download and log into to play, once logged in, you can download various games to your PC to play, but you need to be logged online to access these games, HOWEVER they give an awesome selection of games. Most of these, you have to sign up for a gold account, which requires you to pay a monthly fee, BUT there is a fairly extensive selection of VERY good games that are FREE to play

Hitman: Codename 47, Hitman 2: Silent Assasin, Second Sight

I haven't gotten around to playing these yet, but they look pretty good. They don't have any controller support that I've been able to find though. The ones I will personally played are below:

Mr. Robot - Haven't gotten too far in this game, but it's pretty fun so far (supports PS2 controller)

Blast Miner - Incredibly fun physics based puzzle game, where you try to use explosions and gravity to blast a piece of gold into the goal area. Some of the puzzles are straight forward. Others are barely a step away from impossible.

Tomb Raider: Legend - Far more fun than I originally expected, the combination of gymnastics, climbing, and puzzlesolving are quite fun. (supports PS2 controller, and PS2 controller w/ mouse)

Blood Omen 2 - this is so cliche of the goth/emo vampire crew that I almost couldn't keep playing, but it actually has an incredibly interesting storyline that got me interested in Soul Reaver for PSX, and Blood Omen Defiance and Soul Reaver 2 for PS2. The battle system takes some serious getting used to, since there are some cases where you HAVE to dodge attacks, but it's entirely possible to press the attack button multiple times, and then until you finish that attack sequence, you can't break out of it to dodge. (supports PS2 controller)

Thief: Deadly Shadows - incredibly fun stealth game. it supports both 1st person perspective and 3rd person (I prefer the 3rd person perspective) and you can be as violent or as passive as you feel like. The freedom in that range makes either choice that much more enjoyable. This is actually the 3rd game in the series, but I didn't feel like I was missing out on anything. (supports PS2 controller, and PS2 controller w/ Mouse)

Psychonauts - The art style put me off at first, but this game is so many levels of fun that nothing I can say could do any justice to it. It's both silly and deep at the same time, and the levels are all so DIFFERENT that every single piece of it is an entirely fresh experience.(supports PS2 controller, and PS2 w/ Mouse)

Sam & Max: Abe Lincoln Must Die - It's the 4th episode of the series or therabouts. It's challenging, but mostly amusing. I felt like I was dropped into the middle of the overall story though and I hate doing that.

Steam - Steam doesn't really provide too many free games, but it has a ton of demos, which include Portal and Half Life 2. That means you get to play with both the portal gun and the gravity gun.

The Portal demo limits you to just the first 10 - 12 levels of the game, usually cutting you off before you can get the upgrade to the portal gun that allows you create both portals, however, if you access the developer console(click on the "advanced" under the "keyboard" options tab, check teh box for developer console, and then press whatever keyboard button is set to activate the developer console) while you're playing portal you can use the cheat code "give weapon_portalgun" and "upgrade_portalgun" to access it before you're supposed to be able to.

There's also a special deal that steam runs for if you have an NVidia graphics card that lets you get Half Life 2: Lost Coast demo, and Half Life 2: Deathmatch on top of those.

Half Life 2 and Portal SAY they can accept controllers, but I have NEVER been able to get my PS2 controller to work with them at all. VERY frustrating, but I have managed to get a decent setup on Keyboard and Mouse. I just changed Shift to Run, Space to jump, Alt to Duck, and Ctrl to Walk, then E and Q handle Flashlight and Zoom. That's provided you have a 5 button mouse though. You'll have to play around a bit more if you've only got a 3 button mouse.

The Orange Box is worth buying. It's only $30 and gives you access to 3 incredibly awesome games(5 if you count Half Life 2: Episode 1 and Half Life 2: Episode 2 seperately). One with Incredible story, one with incredible puzzles and game mechanic, and one that's an Online Team Multiplayer with personality. I'll be getting it myself during or after Christmas.

So there you go. 20+ games that are totally free and 3 more that only cost $30 total, all of them are incredibly excellent quality.

Does anyone else have stuff I missed that's of particularly awesome quality and provides mroe than 10 minutes of playtime?

Weres my Super Bejewled HD? -.-

I dunno, post up a link if you have it. I don't like games like Bejeweled and breakout and that type of thing though. I can enjoy them while I'm playing them, but I just can't get into them enough to actually seek them out to play.

May I recommend Battle for Wesnoth?

Dare I suggest Dwarf Fortress in its mighty ultra-hardcore impenetrability?

Battle for Wesnoth - a free turn based strategy game for Windows, Mac and Linux

It's open source, which means there is a lot of really good user created content; factions, campaigns, maps, AI behaviours and the like.

I highly recommend this game, which can be downloaded at

http://www.wesnoth.org/wiki/Download

About 600 mb, so dial up users may want to look elsewhere

cool

That said, the link isnt actually working atm. maybe it's just for me

GAAAAAAAAAAH! Remember to turn off friken stickykeys before you start playing N.

Eternal gratitude for giving props to Psychonauts. Its story is every bit as tragic a BG&E but where BG&E has gotten its laments from the press, hardly anyone acknowleges the injustice served up to Raz.

The game is a great platformer, and truly funny. Has some of my favorite levels ever - the Milkman conspiracy, Lungfishopolis, black velvet and of course, the Meat Circus.

I think my favorite level was Milla Vodello's level. Not for the level itself, but that tiny little back room. That juxtaposition of happiness despite tragedy really hit me to the core.