All-in-one program for creating 2D scrolling games. Compile your games into stand-alone .NET executables or customizable C# source code. The IDE and framework are build on OpenTK, which wraps OpenGL, so generated games can be cross-platform.
Prototype Games aims to provide a Javascript library for quickly and easily creating web-based games that run entirely in the web page, on all modern browsers without requiring plug-ins. It is built off of the YUI (Yahoo User Interface).