Jmol is a Free, Open Source molecule viewer and editor. It is a collaboratively developed visualization and measurement tool for chemical scientists. Jmol is an active project, and there are new features being added to it on a daily basis. Users are encouraged to modify it to fit their needs and to contribute their changes to the project.
X-Plane is a flight simulator that reads in the geometric shape of any aircraft and then figures out how that aircraft will fly. It does this via an engineering process called "blade element theory", which involves breaking the aircraft down into many small elements and then finding the forces on each little element many times per second. These forces are then converted into accelerations, which are then integrated to velocities and positions. This gives X-Plane the most realistic flight model available for personal computers.
OpenCards is flashcard learning software. The basic idea of OpenCards is to use PowerPoint presentations (*.ppt) as flashcard sets. Slide titles are considered questions and the slide contents their answers. Based on state-of-the-art memorization and scheduling algorithms, OpenCards will help you learn any set of flashcards.
kdrill helps people learn Japanese 'Kanji' characters. Its includes a multiple-choice Kanji quiz program that helps people learn Japanese characters with different guess formats and history options. It also has a suite of dictionary lookup functions. Words can be found using a variety of methods including Romaji, SKIP, four-corner, cut-n-paste, radical lookup, and English search.