Memphis motorsports Park if they're having an event.
http://www.memphismotorsportspark.com/
Ducks in the Peabody (make sure you also go up onj the roof top bar to see their digs)
Drive down 61 and visit the casinos in Tunica...even if you don't gamble. Nice car collection at the Hollywood casino.
If you're a blues fan, drive further down 61 and visit the Blues Museum and Ground Zero (Morgan Freeman's authentic juke joint) and n"the crossroads" where Robert Johnson sold his soul to the devil in Clarksdale, MS..