Asymptopia Flashcard System uses Motif and LaTeX to produce, manage, and use attractively formatted flashcards. You load some or all of your "collections" and set the timer for pop-up frequency. The GUI interface and "Collection Manager" make creating and modifying flashcards as simple as pushing a single button. A knowledge of LaTeX is only required when entering special symbols.
lin-seti is a command line program allowing the user to mantain a cache of work units for the Seti@Home client. It should run without any problem on Unix-like systems, including Linux. It is designed to be fully compatible with SETI Driver (similar software for Windows), so you can share the same cache on dual boot systems.
SImg is a software for astronomical image processing. It contains a tool for visualization of highly dynamic images. The package consists of a library and applications which use it. Some of the features are deconvolution (various methods), Video4Linux support, PSF computation, approximation by linear combination of images and polynoms, various color transforms, automatic shifting of image sets (for addition and color composition), and more.
Cerridwen provides geocentric planetary data suitable for a broad spectrum of astronomical and astrological applications, with a focus on our solar system. Among its data you will find, for example, the time of the next sunrise or that of the last full moon, or simply the current tropical position of the sun. It comes with a simple command-line utility and a JSON server, but is also designed to serve as a basis for your own application.
MarsClock is designed to aid engineers, astronomers, Gods of War, Hrossa, and specifically mission controllers for the upcoming NASA MER and ESA Beagle-II missions to Mars. It converts to and from Earth time (Local and UTC) and Mars time (Local Mean Solar Time and Local True Solar Time) for any location.