The Gamebook Engine is a cross-platform engine for
writing gamebooks, such as the "Choose Your Own
Adventure" series or the "Lone Wolf" series. TGE
can interpret scripts that use the "Hyena"
The Open Toolkit (OpenTK) is a set of advanced cross-platform bindings to OpenGL, OpenCL, and OpenAL for C# and other Mono/.Net languages. It can be used standalone (in the spirit of GLFW or SDL) or integrated into GTK# and WinForms applications.