GCompris is an educational software suite with numerous activities for children aged 2 to 10. Some of the activities are game-orientated, but nonetheless still educational. These include computer discovery (keyboard, mouse, different mouse gestures), algebra (table memory, enumeration, double entry table, mirror image), science (the canal lock, the water cycle, the submarine, electric simulation), geography (place the country on the map), games (chess, memory, connect 4, oware, sudoku), reading practice, and others (learn to tell time, puzzles of famous paintings, vector drawing, cartoon making, etc.). It currently offers in excess of 100 activities, and more are being developed.
Card Monsters lets you play a creatures, instants, and sorceries. You to play the game against a computer-controlled opponent. Currently there are over 300 cards, and you can play in constructed, sealed, and draft mode. The program can automatically download all of the card pictures. The GUI is basic but very usable.
KildClient is a MUD client written with the GTK+ windowing toolkit. It supports many common features of other clients, such as triggers, gags, aliases, macros, timers, and much more. But its main feature is the built-in Perl interpreter. At any moment, the user can execute Perl statements and functions to do things much more powerful than simply sending text the the MUD. Perl statements can also be run, for example, as the action of a trigger, allowing you to do complex things.