Playdates are typically arranged between parents of babies, toddlers and children up to age four and are then kid-requested for children ages five to eleven (still coordinated via the parents).
A playdate is at least two children but can include three or more children.
However, the underlying reason is keep the kids busy so that parents can score some action with each other.
So while the kids were downstairs watching Sponge Bob, I was upstairs helping Mommy get some needed stress release!
Johnny - "You don't even know, i think me, Steve, and Christina and a playdate."