Simkin is a scripting language for Java/XML. Simkin is designed to let your users control all or part of your Java application. They write scripts in a very simple scripting language which can be embedded in XML. The scripts can call down into the API you've exposed from your Java classes. You write the mechanism, your users write the policy.
Twisted is an event-based framework for Internet applications. It includes a Web server, an SMTP/POP3 server, a telnet server, an SSH server, an IRC server, a DNS server, a generic client/server pair for remote object access (Perspective Broker), and APIs for creating new protocols. It supports integration with GTK+, GTK+ 2, Qt, Tkinter, wxPython, Mac OS X (PyObjC) and Win32 event loops. It also supports TCP, SSL and TLS, UDP, Unix sockets, multicast, and serial ports. Supported protocols include HTTP, FTP, SMTP, POP3, IMAP, TOC, OSCAR (AIM and ICQ), SSH, DNS, IRC, NNTP, Jabber, SOCKSv4, Telnet, SIP (for VoIP), and XML-RPC and SOAP using external packages. Most protocols are supported as both servers and clients.
PyUI is a user interface library written entirely in the high-level language Python. It has a modular implementation that allows the drawing and event input to be performed by pluggable "renderers". This makes PyUI very portable and scalable. It can run in environments from hardware-accelerated 3D surfaces to regular desktop windows. It was originally targeted as a User Interface for games, but it has evolved into a more general UI toolkit with applicability outside of games.
The Blue Mango Quest is a 3D arcade game that uses OpenGL and SDL. The goal is to extend the pacman-style gameplay in several ways. You see what the main character sees (like in traditional FPS games), and you'll find about 20 items (bonus and malus) that will give you a lot of fun. An easy to use yet powerfull 2D level editor is also provided.
libmousetrap is a C library for the creation and manipulation of compressed, integer-precision 2D cartesian grids populated by integer identifiers. This makes figuring out what is occupying position (x, y) at any given instant easy. Addition of new types of sources for creating these grids from image/graphics libraries is also easy. libmousetrap fully supports transparent regions in the grid system. It was created to provide easy dispatch of mouse events, but seems like it could have other applications.