At one point I was walking along a walkway outside on my way to a meeting and two little lads were approaching in the opposite direction. There happened to be a patch of grass to their right and my left. Suddenly one of the lads launched himself sideways, for no reason I could fathom, onto the patch of grass, and proceeded to roll over, laughing exuberantly. His companion joined in the mirth but resisted the desire to achieve take-off. It occurred to me that it would be rather a good scheme to launch myself onto the grass also but I also resisted the temptation as good sense made me aware that it would be 1. difficult to do so whilst carrying two bags and a laptop computer and also 2. highly disturbing to our two small visitors to discover that at least one of the teachers in the rather grand school they found themselves in was quite mad.
Actually it's misleading to say the boy jumped for no reason - you don't need a reason for a swan-dive when you're that age. I think I spent a fair proportion of my childhood rolling around on grass, at least in the summer months. And a jolly good place to be it was.