There was an Equire article "How to Have Fun" by David Curcurito in the in the June/July 2015 edition. It's a great article all the way through, but the end was a quotation that's kind of changed how I think about having fun:

The thing about fun is it's as important as your job and your health and your home and your money, and it takes about as much work. But it gives you something none of that ever does.

Whatever fun is, it isn't amusing, or interesting, or distracting or simple. It's serious.