Advanced
Programs from the "Advanced Programming in OpenGL" course at SIGGRAPH '96 + a few more that snuck in.

Contrib
Programs that were contributed to the GLUT distribution.

Demos
Demonstration quality programs (usually flashy).

Examples
Fairly simple programs demonstrating many of the features of OpenGL.

Mesademos
GLUT versions of the demonstration programs that come with the Mesa 3D library.

MUI (portable ui)
The portable user interface written in OpenGL with GLUT.

Texfont
A library for creating fonts out of textures.