There was a time I kept wondering what the fuss with TDD is all about.
If by any chance that's something you're wondering too, this is where I understood the sense behind TDD:
These are 2 episodes: part 1 and part 2, total running time: 2h 15m.
If almost 2,5 hours sounds like a lot, the best written summary of the topic I found is: http://fpl.cs.depaul.edu/jriely/450/extras/prof-tdd.pdf (5 pages).