Anything ! Hang out with friends , Try out an instrument [ I recommend the guitar ! ] , Go see a movie , Look into some summer classes a lot of people do that go camping , go on a day trip , maybe even take a nice hike , there is so much out there you can do!
Go camping...by a river or a lake, you can fish, swim, have a campfire, roast hotdogs and make smores....really depends on what you enjoy, if you like outdoors, go horseback riding, whitewater rafting, hiking.
I have planed to stay a month with my daughter, who lives near the beach, it's a quiet place for relaxing and enjoying life,as there 's the pure air, the sun shining and peaceful environment.
In the day time, I can go to the beach under the shining sun, tanning and swimming in the sea. Further more, I will go to visit some famous places there as well.