Blood Pact
These days, the way to assure one's friendship status is to add them on Snapchat or Facebook. In the years of the boomer, this same oath of friendship was done using a blood pact. Kids would cut their hands and then "shake on it," proving that their friendship is bound by their blood...
Merry Go Rounds
You won't find too many of these on the playground these days. Folks used to put their kids on these merry-go-rounds, and then promptly whip the kid across the yard by spinning it so fast. While it might have been fun, it was also too dangerous to survive the test of time.