I wrote about games build in and for MS Excel earlier, and now Gamasutra runs a very detailed feature showing some of the hidden powers of the office application:
"It's time to learn a new 3D game engine name: Microsoft Excel.
It is understood that Excel is an all-round office tool, but probably it is unknown that it has a bunch of features that makes Excel a high-class 3D graphics engine.
In this article I will demonstrate Excel's arithmetical facilities, the embedded rendering subsystems (there are two of them!) and the revolutionary approach which might just cause a paradigm shift. I hope you will discover that Excel effectively and efficiently incorporates practicality, tons of features, the multi-platform portability and the high performance with the unique and futuristic 3D engine features."
Check out Excel Music Synthesizer build on MS Excel 2007.