Peter Rakos wrote an article for Gamasutra today which demonstrates how to hack yourself a simple 3D engine by subverting an Excel worksheet. It’s not going to win any FPS awards, but the fact that you can even get Excel to draw raw shapes blows my mind.
In his demo, the worksheet is used to calculate values for all the polygon vertices and a very small macro loop draws the resulting mesh to the screen.
After downloading the source XLS, run the demo by hitting alt-F8 (option-F8 in Mac Excel). You’ll find the code under the “Tools->Macro->Macros” menu.