Wordplay is an anagram game for Unix/GTK+. It is primarily aimed at Scrabble players looking to improve their word-finding skills, but can also be played for fun. Three types of games are included: word mines (find all words of a certain length that can be formed from the letters of a larger word), hooks (find all words that can be made by adding or prepending a letter to another word), and bingos (7- and 8- letter anagrams).
Zaz is an arcade action puzzle game where the objective is to get rid of all incoming balls by rearranging their order. Currently it includes 20 different levels and two modes of gameplay. The engine allows for easy custom level creation with unlimited number of paths, different speeds, ball-sizes, and rules. A 3D accelerator is needed for decent gameplay.
Omnitux aims to provide various educational activities based on multimedia elements (images, sounds, and text). Possible activity types are associations, puzzles, counting activities, etc. There is support for multiple languages and multiple screen resolutions (by using SVG vector graphic files and high quality bitmap files). Omnitux activities are described in XML files, so it is possible to create new activities without modifying the program.
Hex-a-hop is a puzzle game based on hexagonal tiles. There is no time limit and no real-time elements. The objective is simply to destroy all the green hexagonal tiles on each of the 100 levels. As you progress through the game, more types of tiles are introduced, which make things more difficult and interesting (hopefully).
Octaspire Crates! is a scriptable, skinnable, extensible, and relocatable 3D action puzzle game. All the missions, game entities (or crates), game states, and configuration of the game engine are implemented as plain text Lua-scripts. So, if you know Lua, you can write new game entities, game states, missions, and levels with any text editor, without any special development tools. New skins can be created with any image editor that can save .png images, dropped into a new subdirectory under the resources/textures directory, and changed in the configuration file config.lua. Crates has also its own (simple) implementations for all the different container classes it needs (like vector, string, and so on) to keep the external dependencies fewer.
Superficially, Dominoes on Acid is a solitaire variant of Dominoes with weird colorful tiles (and this view is enough to play the game). But on a deeper level it is a GUI for natural deduction. Every completed domino is equivalent to a proof of a tautology in classical propositional logic. The game can be played online as an applet or offline as an application. It is built on a simple isometric engine that can be used independent of the game.
GNUSTEP Live CD contains a lot of software for GNUstep, a free implementation of the OPENSTEP framework (which is also directly used in Mac OS X as Cocoa). It includes excellent applications for RAD (GORM and ProjectCenter). The CD is available for i486, AMD64, Apple Mac PowerPC, and Sun UltraSPARC computers.