When we were at university that all came under the general heading of Folklore. Our best discovery along these lines was the Opies' The Lore and Language of Schoolchildren. Iona Opie has another book called People in the Playground which is more like psychological observations along with the "alarmingly inappropriate" things children say (I'm reminded of the anecdote about JFK Jr. saying "G'night, Poopy Head" to his father, who responded "You're calling the President of the United States a poopy head?").

They are a bit biased as the Opies believed in gender biodeterminism, but so what. They're a terrific source.

The only one we ever did or saw done was "Playmate".