Before the knees went south, I used to love running. I ran (and skied) X-country in HS, and when the course was free of snow, I used to run it twice after school - then, I'd grab my stuff and run/jog home, over 3 miles away. I loved my ski-patrol work during those years, and when I went to college, I volunteered to teach downhill skiing in an intramural setting.
Most fun was running open-mike blues/rock jams at a local tavern on Sunday afternoons. It was only good for $125/for 4 hours, but it was great fun when parents would bring their kids to participate. We had some really talented pros and semi-pros showing up, too (close friends from HS on, in many instances) and it was fun to provide a supportive environment for young players, encourage them to take leads, etc. The most fun was when a kid had asked something like "how do you do those double-stop bends?" only to have them come back a week or two later and try to work those techniques into a song. Even better was when they'd come back after more practice and pull a technique off smoothly, grinning from ear to ear.