Tennessee Aquarium has a deal on memberships:
All memberships include unlimited Aquarium admission, discounts on additional IMAX tickets, discounted River Gorge Explorer cruises, special events, and a FREE subscription to Riverwatch, our full-color, quarterly publication. Tennessee Aquarium Members also get discounted admission to Creative Discovery Museum, Knoxville Zoo, Nashville Zoo at Grassmere and Dollywood!
Family Membership - $115 (admits two specified adults and their children age 18 & younger)