Other Free Games?

[Specialist290]

Figured I'd kick off a little discussion here...

So, besides UFO:  Alien Invasion, what other free (whether freeware, open-source, etc.) games does everyone enjoy?  I'll start off things by listing a few of my own:

Dwarf Fortress:  Odd city management / roguelike mashup that's insanely complex.  I've never actually played a "full" game as such, but I certainly appreciate the attention to detail that goes into the game.

Warning Forever:  Japanese arcade-style "bullet hell" shoot 'em up.  You fight an endless sequence of bosses that adapt to your strategy.

Oolite:  Open-source remake of the classic space sim Elite.  Has about a thousand expansion packs you can add to add new ships, missions, and even star systems.  Really friendly community, too.

Anybody else got any recommendations?

[Dark]

The White Chamber - Really great (except a bit short) horror adventure.

Egoboo - Fun RPG with a unique charm to it.

Battleships Forever - 2D real-time space tactical game inspired by "Warning Forever".

Dune 2: The Maker - A project to remake good old Dune 2.

[maackey]

Complete Annihilation -- An epic multiplayer 3d RTS inspired by Total Annihilation with spectacular graphics (especially for a free, open source video game) and fast action oriented gameplay. I've never been engrossed in any game as intimately as this one (even ufo:ai takes a close second )

Battle for Wesnoth -- A 2d turn based fantasy hex game with pretty nice graphics and good polish. Not nearly as good as CA, but it is a lot more popular. (lots of singleplayer campaigns and ability to join/spec in the middle of multiplayer games is pretty nice)

Liquid War -- A very unique and interesting game that involves liquid blobs battling/consuming the other liquid blobs to win.

Scorched 3d -- A turn based game where you shoot other tanks with an arsenal that will blow your mind away. Fun is exponential with the amount of friends playing at the same time.

[Jeep-Eep]

The Ur-quan Masters.
http://sc2.sourceforge.net/
Aleph 1.
http://source.bungie.org/index.php?title=Get_Marathon