Get your tickets to see a game at Stade Olympique. If there's nothing scheduled while you're in town, you might like to check if they give a tour of the grounds.
You'll find this sporting facility in Sousse Jaouhara. Once you've explored everything you can at Stade Olympique, have a look at nearby Sousse Beach, Port El Kantaoui Beach, and Ribat of Sousse.