On the last leg of the school hol's and out of ideas? Here's a 30-second Harry Potter Lego animation that I shot in two hours with my 8-year-old boy. It's called Platform Nine and Three-Quarters. He directed and I was on camera. It's our second attempt at Lego animation. (Our first attempt is below.) We used a Canon EOS 50D camera then imported the stills into iPhoto. We accessed the photos via iMovie and edited it, adding free sounds from iMovie and www.freesound.org.
You can also use your web-cam and a free program called Frame Thief if you don't have access to a camera. Hope you create something fun. Good luck and let me know when you've uploaded your movie.
Our first attempt at Lego Stop-motion animation using a laptop web-cam and Frame Thief.