Planking
Find a spot anywhere and plank facedown.
That's it. That's planking.
In 2011, the trend of planking was hot in the States, and even had people challenging each other to do the best plank. Of course, this led to dangerous attempts for social attention (imagine someone planking on a bridge's ledge).
Even as a kid, I found this ridiculous. We often find ourselves quite board as a society. (Board? Like a plank? Instead of "bored." It was funnier in my head. Leave a puke emoji if you hated it.)