Cool ideas for summer?

Hey!

A few friends and I want to get together more often in the summer. We're farmers, and we own two fields and a meadow right next to an idyllic river. We want to put a few benches on the meadow (right next to the river). We also want to add a fire pit so we can have barbecues. We also want to take a quick dip in the river every now and then. We've been thinking about cooling off with a beer in the wet sand next to the river, since it only gets about 18 degrees Celsius in the summer. Does anyone have any other ideas? Thanks.