Wine Country Activities:
Visit a local winery: http://calistogavisitors.com/wine-wineries.php
Notable: Chateau Montelena (of the 1976 Paris blind-tasting fame) and Sterling Vineyards (where you arrive via aerial tramway).

Golf:
http://www.napacountyfairgrounds.com/golf.htm

Local Biking:
http://calistogabikeshop.com/

Parks and Hiking:
http://www.parks.ca.gov/?page_id=477
http://www.petrifiedforest.org/

Spas and other dirty ideas:
http://www.drwilkinson.com/
http://www.goldenhaven.com/spatreat.html
http://www.lincolnavenuespa.com/

Balloon ride:
http://www.napavalleyballoons.com/

Horses:
http://www.triplecreekhorseoutfit.com/