PRPVis (Probabilistic Roadmap Planner Visualized) is a probability-based method for planning the movements of objects with several degrees of freedom, such as robots. The program PRPVis provides an interactive visualization of the algorithm intended for teaching the algorithm to students.
Showkeys is a simple program to display keys being pressed on the screen. It is useful while making presentations and screencasts. The audience will be able to see the keys being pressed. It is similar to key-mon. Key-mon has more features than showkeys. but the latter solves some specific problems: it doesn't use GTK/GNOME; uses libxosd to display keys directly onto the screen; has no floating windows to that always need to be on top (which is very useful if you're using a tiling WM like Xmonad); and has keystroke history. key-mon has keystroke history, but doesn't show modifiers. showkeys does, using an Emacs style key notation.
Klen-library is a program for creating electronic books. It consists of three modules, for editing books, reading books, and creating tests. It offers password protection of every book and the editing mode. The print function makes it self-sufficient, as it allows creation of books without using third-party text editors. It uses SQLite, so you don't have to install a database server. It can export to the XWB, HTML, TXT, PDF, PostScript, and RTF formats, and can import from XWB, HTML, and TXT.