OpenDKIM is a DKIM implementation with both a C library for writing your own applications and a milter-aware filter for use with recent MTAs.
milter manager is a flexible and low administrative cost anti-spam system that can be used with MTAs that support milters like Sendmail and Postfix. It provides an effective solution by combining a range of existing milters.
A music player with a waveform seek bar.
A TimeMachine style backup system for Linux.