I too am no expert, but it seems like you really want to add things that will either diversify you or show a lot of motivation.
For example, I might list that I train for Ironman Triathlons in my spare time (however, if I did I'd be lying, because I have no desire to do all that work

). Or I might put in there that enjoy sometimes lobbying on behalf of a charitable organization. Hobbies that relate to your career goals seem like they'd be good as well - maybe if you want to work in the tech industry and you like to build computers in your spare time that might be a good thing to mention.
I'm realizing that I'm going to look like lame when i fill this out. I'd better get some more organized activities, because my hobbies are pretty unimpressive.
Maybe someone can give advice as to whether it matters. If you fill it up it seems like the worse that could happen is that they ignore the ones that they don't see as important.