The Chemistry Development Kit (CDK) is a library of Java classes for chemo-, bioinformatics, computational chemistry, and chemometrics. It provides important algorithms like substructure search, SMILES, Gasteiger charges, QSAR descriptor calculation, 3D structure generation, 2D layout and rendering, many IO formats, atom typing, and more.
The Interreality project is a collection of Open Source, Free Software projects based on the Virtual Object System (VOS) platform. The goal is to develop a free and open platform for multi-user 3D virtual reality games, applications, and interactive, collaborative 3D virtual spaces. VOS is a powerful and generic network object framework designed to support a variety of high-performance applications. It is the basis for Ter'Angreal, a general-purpose browser application for entering and participating in 3D worlds.
Gangplank is a Computer Mediated Communication (CMC) system (or "chat server") which supports real-time communication between users, currently using a text-based user interface. It runs as an Internet server which implements the standard telnet protocol, so no special client program is necessary for users. Server-side processing provides input editing/history and terminal- handling features over the telnet connection for standard ANSI terminals. This code has been in production use on a private server since early 1993. This single-process server is fast, efficient and stable.
The NumericalChameleon converts numbers with a precision of up to 1000 significant figures. It supports more than 3200 units in 82 categories, including lengths, areas, volumes, durations, bits & bytes, angles, temperatures, exchange rates, Roman numerals, spoken numbers, all 35 radixes, unicode, colorcode, int. dial codes, timezones, date calculations and more. You have unlimited access for adding, modifying, and deleting categories, units, and icons. Update exchange rates with the GUI or at the command line. All configuration data are stored in flat files.
pydance is a dancing game written in Python, formerly named pyDDR. The idea is simple. There's a floor mat with arrows, and the game scrolls arrows up the screen to the beat while playing a song. When the arrows reach the top of the screen (not sooner and not later), the player hits the corresponding arrow on the pad, and given that it's hit on time with the beat, points are scored. Based on how well the dance is put together, s/he is graded at the end of the song. Both keyboard and mat play are supported.
Tkinter is Python's de facto standard GUI (Graphical User Interface) package. It is a thin object-oriented layer on top of Tcl/Tk. To use Tkinter, you don't need to write Tcl code, but you will need to consult the Tk documentation and occasionally the Tcl documentation (since Tk's low-level event handling mechanism is considered part of Tcl).