This week we're working with forms in two of my classes. The PHP is a little more complicated than other things we've done, but I think I'm still understanding it well enough. We're using some borrowed code, so understanding it takes more time than when you make it yourself.
reCAPTCHA is awesome. I'm blown away by what a good idea it is! reCAPTCHA works by using text that was hard for computers to read while scanning old books and crowdsourcing the problem while simultaneously making sure people and not bots are submitting real data. So cool!