That's funny because in high school my friends and I all dug this pit in the dunes at the beach. We'd spend a few hours a week digging, after a month we had this huge pit we could hang out in an not be seen from the beach. Many a party on the beach. We could also keep all our stuff in it. Pretty pointless but it was fun and gave us something physical to do when there were no waves.

Haha that's great. Same exact thing happened to me when we were on vacation in Florida earlier this year. I started digging a hole, because why not? Kids around immediately took notice and wanted to help.