GeoToad is a geocaching query tool to help speed up the boring part of geocaching: choosing the cache and collecting the data. It allows you to generate any kind of complex query you want, and the program will go and poll the Geocaching query, grab the data, and output it to any format you want. The Geocache info can be synced straight to your GPS, iPod, PDA, or cell phone in over 20 different formats.
SaVi is satellite visualization software that lets you create, run, examine, and modify satellite orbits in two and three dimensions. Simulations of Iridium, Globalstar, Galileo, GPS, and other satellite constellations are included. SaVi requires Tcl and Tk on a system with Unix libraries. SaVi works well with the 3D renderer Geomview. Geomview is optional, though recommended for its 3D rendering capabilities.
A modified version of the rwhod daemon as distributed by 4.3BSD once upon a time. Features include being able to send notification to a specific server (instead of broadcasting to everybody) and using network byte order for the files stored in /var/spool/rwho. It can also filter which hosts to listen to.
Minotaur is a generalized extension which lets you run Python scripts from Tcl, or Tcl from Perl, or any of the other combinations. Minotaur works by loading the appropriate shared library into another script language's context. So, for example, running Tcl from Python means that the Python main program imports the Minotaur extension, which in turn loads the Tcl libraries - thus Tcl becomes "embedded" into the Python runtime environment (which is similar to embedding Tcl in a normal C program). As involved as that sounds, performance is already surprisingly good, and the capability is turning out to be quite useful. Minotaur 0.1 is an alpha level release, meaning: it works, aside from a few quirks and bugs, but its API and implementation might still change in incompatible ways in future releases.