Enjoy the beach and the sea. Most of the beach is privately owned by the various hotels, so if you are staying at a hotel that does not offer beach access, you'll have to use the public beach at the end of the Gran Viale, most central, which is very nice but a bit crowded.
Rent a bike from one of the numerous shops at the Gran Viale and explore the island.
Partake in golf and tennis, as Lido is more about relaxed leisure than frantic tourist activities.
Stroll along the quiet, shaded streets, people watch and window shop.
Visit the natural Oasis in Alberoni, pretected area from WWF.
Meditation and relaxation in the meditation center Energy Darshan (http://www.oshoyatrilandv...)