OpenGL Utility Toolkit
GLUT the OpenGL utility toolkit, is a cross-plattform API to create windows and mouse/keyboard I/O ontop of OpenGL; one can also create simple geomtric objects like cubes, spheres or teapots. It was firstly developed by Mark Kilgard on SGI systems, and later ported to WIN32 by Nate Robbins. Now there are implementations for almost every system where OpenGL is available.
GLUT on SGI Systems
Nekoware has a GLUT 3.7.25 package.
For an introduction to GLUT (after installing one of the above packages), issue a man glut in a terminal window.