Everyone does *something*, but a lot of them have hobbies that they regard as too boring to others to discuss. It might be as common-place as trying to raise their children [a real time-sink, but doing it well requires some focus]. It might be as disorganized as trying to see every old movie of a particular genre, with no real intent to use the culture gained therein.

Some people don't think of these as hobbies, but just do them: yard maintenance, cooking nice dinners [nicer than I would], finding nice wine [or whiskey], lingere, scrapbooking, church-groups... Granted, not all of these are as wide-ranging as SCA or LARPs, but its what people do.