MisterHouse:
MisterHouse is a Unix/Windows home automation program written in Perl. It can respond to voice commands, Web browsers, time of day, serial port and X10 data, external files, etc., and can speak via Text to Speech engines.

GPLIGC:
GPLIGC is a program to analyse IGC flight data from GNSS flight data recorders used by glider pilots. It uses Perl/Tk and gnuplot, and can view data in 3D with OpenGL.