I've combined 2 favorite things to do: biking and geocaching

There are thousands of cache boxes hidden all over
the world with 'treasures' in them. I found out while searching the
net for a gps last summer. The boxes are maintained by whoever put
it there. Pocket-sized objects are transported by the players around the
world. This gives me a destination to bike to and takes me to different
roads and places. It's fun because it can involve the whole family,
the kids can get a 'new' toy or treasure they found. Some are hard to
find and some are easy. Some in the city and some in the mountains.
Two rules: 1.If you take something, leave something.
2. You can not be seen!! Obvious reason on the second one and it
adds some stealthy fun. Anyway, I just thought I would share. Check
out this site for more info or to join in.
http://www.geocaching.com/