OpenUnivers creates a visual simulation of the Solar System's bodies in 3D. It's main distinction from other programs of this type is that OpenUniverse renders in realtime, allowing you to view all the planets, moons, and other heavenly bodies as they move along their paths. You can zoom around and view the Solar System from any angle. OpenUniverse runs under Linux, most UNIX systems, and Windows.
Orac is a GUI tool for Database Administrators written in Perl, Tk, and DBI. It organizes many useful DBA scripts into a nice graphical interface, for collecting statistics on your database, or diagnosing problems. It currently supports Oracle, Sybase, and Informix. Richard Sutherland's DDL::Oracle Perl module has been integrated with the current version for the Oracle side of things, greatly improving the Oracle developer options on the program.
OSKit is a development kit lets you easily build your own kernel that can run on bare hardware. It has lots of component libraries and example kernels, and has almost everything you need to build a new OS. It includes full documentation, CPU schedulers, simple virtual memory, most Linux filesystems, several networking libraries including TCP/IP, most of Posix, lots of device drivers, and much more. Almost all components are optional, and all components are designed to fit into other operating systems if desired. A compatible version of the Kaffe JVM is also available.