Went to a great session last night at the Yorkshire Extreme Programming Club, a intro to Test Driven Development using just Excel. The presentation was given by Clarke Ching, you can find out more about him and this presentation on his blog
I just had not occurred to me that Excel is a great way to show TDD principles to people who are not developers, such as project managers and business analysts. It is interesting how using TDD, refactoring and pair programming (well the whole room actually) anyone can see how to get a complex business requirement to elegant code in nice easy steps.
I think the key new fact for me was not to write too many test too soon, I know in the past I have tended to write many tests then tried to code. I can now see that doing a few tests, a bit of code, then repeat is a far better model, you don't get daunted by the number of failing test, and you don't write test for codes you realise you will never need.