AcidIM is an Instant Messenger application written in CGI-Perl. Users can send and receive messages as well make video conferencing (assuming that camserv is running on users' machine).
HardInfo is a system profiler for Linux systems.
It can display information about the hardware,
software, and perform simple benchmarks.
SuxPanel is a GNOME panel clone written from scratch using plain GTK+ 2.
The projects's license is GPL, although I was unable to find where to download the sources.
Interactive geometry program.
A multi-format module player.