http://www.tnaqua.org/KidsTeachers/Homeschool.asp
It is coming pretty quick, there are classes too that start in just two weeks.

If you are planning on going reply here so that maybe we can meet up. I copied the following information from their site:

Our Home School Day this fall will be on Monday, September 28, 2009. Mark your calendars. We are offering great discounts for admission to the Tennessee Aquarium, the IMAX Theater, and the gift shops in each facility (See special rates below). Free animal programs will be offered in the auditorium from 11 am to 3 pm and special behind-the-scenes tours will be offered just for that day. So don’t miss this special day of fellowship with other home school students and their families.

Prices:
HS Students (on HS Day only) pay:
$6.50 Aquarium
$5.00 IMAX
$10.25 Combination Aquarium and IMAX

HS Parents (on HS Day only) pay:
$19.95 Aquarium
$ 7.75 IMAX
$23.95 Combination Aquarium and IMAX

Home school students and parents will receive a 10% discount at the Aquarium Gift Shops. Members of the Aquarium who are home school students or parents can receive a 20% discount on this day only. Tickets for a guided behind-the-scenes tour will be available for $5.00 on this special day and must be purchased at the ticket office when you purchase your tickets for the Aquarium or IMAX. (These discounts are only offered during our home school day.)