The kids are sure to sleep soundly after frolicking by the water at Nabeul Beach. Search for cute critters like crabs and snails, stick a toe in the water or throw a Frisbee around!
When you've finished exploring this Tunisia stretch of coastline, why not make your way to Maamoura Beach, Omar Khayam Beach, and The Great Mosque? They're not very far from Nabeul Beach and also a hit with tourists.