Hiking seems to have taken on something of a niche quality, but this might be because of the high humidity during warm months. Humidity nonwithstanding, Nashville boasts 132 trails in the metro area according to Trails.com.
Nashville Swing Dance Club meets at the Skate Center in Nashville, and focuses on "diversity in dance." They no longer focus solely on swing. They teach Foxtrot, West Coast Swing, Rumba, Cha Cha, Two Step and American Tango among others.
If you're interested in more country oriented dances, check out the Nashville Country Dancers who even have contra dancing.
WalkBikeNashville.org is an organization dedicated to making it easier and safer for bicyclists and pedestrians in the city of Nashville. They have a variety of resources designed to make it easier for you to get around and do so actively.
We also love RideForReading.com. RideForReading helps promote literacy by using bicycles to deliver books to children in low-income families.