I just read an interesting report about one of those geekier hobbies... satellite spotting. Specifically people that spend time looking for, computing the orbits of, and tracking spy satellites (and I'm sure probably anything else that gets put into orbit)
For example, take the spy satellite that got shot down the other day. The govt talked about the fact that it died not long after being launched and that it was going to crash. What they didn't do was say very much about the satellite itself. That information came from a hobbyist who, along with fellow satellite spotters around the world, spends a lot of time watching the skies.
Thing is, I don't get why those super secret government agencies get so nervous about things like this. I mean, I am not a hamster, if they want a satellite that can't be seen from the ground then they've got some serious work to do developing practical invisibility... since that's about the only way to prevent anyone... hobbyists or governments, from tracking anything in orbit.