Memview is a realtime visualization program which shows the memory state of another running program as a graphical image. Memory addresses correspond to pixels in the image, and as memory is accessed, the display will animate to show which parts of the address space are currently being referenced by the program.
Enterprise Reporting Server (Birt) aims to be a Free Software replacement for the standard Birt webviewer. Some its features are: uploading and managing Birt .rptdesign files, user accounts with role-based access controls, fine-grained permissions on reports, and scheduling of reports (using Quartz Enterprise Scheduler).
GTKMathplot is an interactive plotting program based on GTK+ and the Cairo graphics library. It can display bidimensional curves, tridimensional curves, and surfaces from Cartesian or parametric equations describing the mathematical objects you would like to visualize. It is designed to be intuitive for high school students with good mathematical knowledge. University students of engineering, physics, mathematics, or natural sciences should need no explanation at all to start using it proficiently.