Tux Paint is a simple and entertaining drawing program geared towards young children. It has a simple interface, sound effects, and a cartoon character (Tux, the Linux penguin). Along with drawing brush strokes, lines and shapes, you can also enter text and place "rubber stamp" (or "sticker") images on the picture. Tux Paint is extensible, and could be useful in an educational environment (such as a grammar, elementary, or grade school). It's portable across numerous platforms, and runs well even on slower systems like the Pentium 133MHz.
Asymptopia Crossword Builder (Math/Text) is an application that runs in any modern Web browser, but does not require an Internet connection (if it is installed locally). The application was designed to allow teachers to quickly produce well-designed, challenging activities. The application features a configuration panel where the user can either enter their own word-hint pairs, or generate math-crossword problems via a single button. The math functionality generates word:hint pairs like: "four:7/x-3/8=11/8", where the hint corresponds to the problem, and the student would write the letters "four" in the corresponding boxes of the puzzle.
Step Into Chinese is a flexible language-mining tool to assist English speakers seeking to understand the Chinese language. Inside is an extensively cross-referenced data structure which allows the user to pursue deeper understanding of contexts, for example, by "locking on" to a particular Pinyin context and viewing successive instances of the same morpheme used in similar contexts.
Morris is an implementation of Nine Men's Morris that also supports several rule-variants and different board layouts (including Morabaraba). You can play against the computer, or play against another human opponent. The computer opponent learns from previous games and tries not to make the same mistake twice. This ensures continuous variation in game play, should you manage to beat the program. Furthermore, the program can give move hints and provides unlimited undo/redo.