FakeNES is a portable, Open Source NES emulator that is written mostly in C, and uses the Allegro library for cross-platform capabilities. The officially supported platforms are DOS, Windows 9x/2k/Me/XP, Linux, FreeBSD, QNX, BeOS, and Mac OS X.
A multiplatform file watcher. Pretty much like tail with a GUI.
A Web-based document management system with a Google-like search engine.