I/O Fender provides a simple and efficient binary buffer interface that is independent of the backstore used. The interface is much like the traditional file access interface; iofender buffers expand as needed, and an offset is kept for determining where in the buffer operations are applied.
netics is an extensible network statistics collector. It feeds the data stream (after it strips off the appropriate protocol headers) to modules gathering statistical data, and then displays the results at specified intervals, either in a "progress bar" mode or as raw statistics. Currently it supports two statistics, both involving entropy: LZW compressibility, and Ueli Maurer's universal statistical test.
trickle is a lightweight, portable, per-application bandwidth shaper. It works in collaboration, has peak detection, and does smoothing. trickle works entirely in userland and does not require root to run. It has been developed on OpenBSD and is known to run on Linux, FreeBSD, and Solaris.
xsay is a notification tool for the X Window System. Simply running xsay with a message as an argument will display that message in a "bubble" on the top-right corner of the screen. If there is already a message displayed, the entered message will be queued and displayed once the user acknowledges the current message. The user can acknowledge a message by clicking on it or by running "xsay -d".