On the water
If I had a fairy godmother of sports equipment (and a fairy godmother of storage space I suppose), I would totally ask her for paddle boards or ocean kayaks for my family. I love both of those activities. They provide the perfect combination of exercise and exploration. We live close to a calm bay area of the ocean, so I can picture us using them all spring and summer.
If I had to pick one- it would be the paddle board. It is a full body work-out and is the coolest sensation of moving along the water.
If you live near the water, or vacation there, I recommend looking into trying some paddle boarding or kayaking. It is a great way to spend the day....