Coccinella is a cross-platform communication tool with a built-in whiteboard for improved collaboration with other people.
SFLphone is an SIP/IAX2 compatible softphone. The goal is to create a robust enterprise-class desktop phone. While it can serve home users very well, it is designed for intensive corporate use.
A ProjectPier appliance that is easy to use and lightweight.
A tool (with a GUI) for steganography.