Music! Lots of live music. Country & western is the prominent venue, but there's plenty of other styles including rock (old & new) and rhythm & blues.
If R&B music suits you, be sure to catch the Stacy Mitchart Band at B. B. King's Blues Bar on 2nd Avenue North in Nashville. Check the band's web site at http://www.stacymitchhart.com/
for schedules. One of my favorites - I listened to them whenever I went to Nashville. I hope to see them again some day!
Also, take a day or two to visit Chattanooga, about 2 hours away. Downtown Chattanooga has plenty of attractions including a scenic waterfront along the Tennessee River, the Tennessee Aquarium, and a piece of America's history. There are a number of major Civil War battle sites near Chattanooga - The Chickamauga Battlefield and Lookout Mountain among them.
If you like white-water rafting, be sure to spend a day on the Ocoee River, east of Chattanooga. If the season's right, the river provides quite a ride.
I'm sure that a couple of Nashville natives will give you much more information.