We went by in the afternoon with the across-the-street neighbor girls and their nanny.
There were something like 15 kids there and 5 nannies. These are all I could wrangle at the time. My overall impression was really very positive – everyone played together, everyone shared, no one hit or cried. Johanna, the nanny from across the street said that in the mornings between 11 and 1 you can often find 25 kids there.