Cellular manager for mobile phones/modems
Gammu is a cellular manager for mobile phones/modems. It contains libraries and functions for ringtones,logos,phonebook,SMS,etc. (used by external software), a command line version (with backup/restore) and SMS gateway (with MySQL and PostgreSQL supp
Servlet container extensions that help web developers write full featured Java web applications.
Library that allows you to check the battery level and set the volume limit of your Zen Stone mp3 player. It's also a simple example of how to communicate with USB mass-storage device with libusb.
A library of 3-D tools for vector algebra. Already in wide use for 3 decades in crystallographic applications.