Galaxis is a curses-based clone of Christian Franz's game Galaxis for the Macintosh. It is a logic puzzle--you must drop probes in space to locate four lifeboats from a distressed interstellar liner. Can you locate them all before you run out of probes and they run out of oxygen?
game control program helps you administrate gameservers (it's written for Q1 and Q3, but works for others). It is highly modular and therefore extensible. With the current modules, it can start/stop servers, create and rotate logfiles, allow remote administration via telnet, and kick misbehaving players automagically (according to a rule set).
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.