Here's an example that fits comfortably in 5 minutes--if your audience knows elementary calculus: http://www.cs.dartmouth.edu/~doug/powswer.html It depends critically on lazy evaluation, which knocks out a lot of competing languages right from the start. The five-minute version would begin with power-series addition--trivial. Then comes multiplication--an eye-opener. No subscripts! No worry about how many terms to carry in intermediate results. That's about all you have time to really derive. Go on to mention that division is about equally easy. Then allude to substitution (also called composition) and its inverse, reversion. Lots of finicky papers have been written about reversion over more than two centuries. Throw that one-liner on the screen side-by-side with Algorithm S (which is only pseudocode!) from Knuth section 4.7. That should convince the most skeptical observer. Doug