Freeware Audio Analyser

http://audio.rightmark.org/index_new.shtml

The Fan Story

http://beale.best.vwh.net/measure/fan/fanspeed.html

A funny (and true) story involving some interesting calculations of air flow, velocity, thrust, etc.

Make Your Own Beer Labels

http://www.beerstore.com.au/make-your-own-label.asp