Our first project in Computer Graphics was to make a simple heightfield. A heightfield is basically a 3-dimensional rendering of a 2-dimensional image. It's like a topographical map turned into 3-D.
If you have a linux computer, you can try it out. Download it here: OpenGL heightfield program.
See the README for instructions on how to run the program. You'll need the OpenGL and GLUT libraries on your system. Only the binary is provided.