Relax on the beach or try your hand at crabbing
Fenwick Island State Park is a gorgeous state park on southern border between Delaware and Maryland. A lot of the beach side areas in Delaware and Maryland are, for better or worse, highly developed with lots of homes, cars, shops, and restaurants. That's not to say that they aren't pleasant, but sometimes you just want a nice natural beach...no crowds, no noise. Well, luckily we still have Fenwick Island State Park.
If you want to relax on the beach, head to the ocean side of Fenwick Island. There are snack bars, a changing room, and lifeguard on duty all summer long. The water is a bit chilly, but the sand is soft and the view is beautiful. The beach, by the way, is huge. Don't worry about getting there at 8 in the morning to reserve your spot. There is more than enough room for everyone and the beach never gets all that crowded anyways unless you're talking about holiday weekend.
If you're not the beach-bum type, then consider heading to the side of the park that faces Little Assawoman Bay. You can go clamming or crabbing in the shallows of the bay and, who knows, maybe even get enough to have your very own clam-bake in the evening! If you're going to boat out in the bay, make sure to put your boat in at the Assawoman Wildlife Area and when paddle (or motor) your way across the bay.