The satpass script provides satellite visibility predictions, given the position of the observer and the NORAD element sets for the desired satellites. It can acquire the NORAD element sets directly from any site supported by Astro::SpaceTrack. It can acquire the observer's latitude and longitude from http://geocoder.us/, look up star positions in the SIMBAD catalog, and more.
setirotate automatically spawns the SETI@Home commandline client, rotating it through work units in a work unit cache. You can configure the number of work units to store, the number of processes to run simultaneously, the number of simultaneous result-upload/workunit-download transfers, the time interval within which its allowed to perform said transfers, and the timeout interval for when a transfer fails. It will immediately start working on a work unit when the previous one finishes, while uploading the newly finished result (if the upload interval permits) in parallel. It strives to always keep something running.
skyviewer is an OpenGL-based program to display HEALPix-based skymaps, saved in FITS format files. The loaded skymaps can be viewed either on a 3D sphere or as a Mollweide projection. In either case, realtime panning and zooming are supported, along with rotations for the 3D sphere view, assuming you have a strong enough graphics card.
wmJupiter is a Window Maker applet which features the planet Jupiter. It allows you to keep track of the Great Red Spot and the current distance in astronomical units (AE). The four Gallileo moons (Io, Europa, Ganymede, and Calisto) are also displayed when they are near the planet.
x10ephem computes sunrise and sunset times. It consists of a library and an assortment of utilities. The most useful utility is x10events, which parses crontab files and updates the time fields to track sun events. Combined with an X10 interface like HEYU or X10, this allows the scheduling of lighting events to follow the changing seasons and daylight savings time automatically. This application does not depend on X10; it can be used for any crontab entry you like.