I have a few uncommon hobbies and interests, but everybody knows about them, lol
I collect heirloom and rare narcissi (daffodils), and this spring I'll be starting a flowerbed especially for heirloom roses. Basically- if a flower has an old history and can be grown in my zone 5b, I'm all over it. =)
Cemetaries- sounds really morbid, but I love beautiful cemetary statuary, 'specially from the turn of the century. My husband and I take drives out in the country specifically to find really old graveyards so we can explore 'em. Hubby's a big Civil War amateur historian, so he loves finding the old veterans' graves.
Local legends and folklore. The creepy ghostie stories and sites like the popular "Crybaby Bridges" that pop up everywhere. I'm more interested in the stories behind them then the actual existence of ghosts, lol
A few years ago, I was in a group called "Frogwatch", where you go to specific area and collect data on the frog population to send in. That was a blast!
Urban exploration. This is a risky interest, since sometimes it does involve, well... trespassing in often condemned buildings. Don't do that too much anymore. =)