Day 5 has Santa determining which of a list of strings are naughty or nice based on a set of criteria. We build three validators in part one, each using regular expressions to solve the problem. As expected, part 2 changes the requirements a bit, so we build 2 more validators using a Test-Driven development methodology with phpspec.
Sorry about the scratchy sound. I think it ended up recording from my headphones instead of the computer and it was probably rubbing on my shirt or something. :(