Lots of options, including the following: stroll the grounds of the island's Butterfly Farm; head up to Loterie Farm for hikes and a ride on the adventure center's zipline; browse for souvenirs and bargains on Phillipsburg's Front Street and in Back Street's Market Place; hit the water at Dawn Beach; take a ride on the Seaworld Explorer, a semi-submersible, on which the bottom deck takes you about five feet below the surface. Of course, you won't be able to do all the above in a day, but any of the above should keep you plenty busy!