We had a snow day in Manhattan. That is to say, there were a few inches of snow, and the Board of Ed declared it a day off for New York City public schools, to the jubilation of many boys and girls.

Meanwhile private and independent schools had not yet opened after the winter  break. And anyone who was planning to leave early Friday to go skiing for the weekend or to their weekend homes heard weather predictions varying from a dusting of snow (Manhattan) to blizzard conditions (on Long Island) and decided to stick around town for the weekend.

That means one thing: lots of people who would otherwise have been away were here and the hills in Central Park were jam packed with kids and parents. And sleds.

There are two things that really stuck me about these kids (and moms, dads and caregivers) on a hill. First, gravity imparts lessons you just can't fight. Unless your mom, dad or caregiver is really indulgent or you are really little, if you want to ride it down, first you have to haul it up.

It seems like a small thing and an obvious point. But it is a huge lesson for kids in a town where we tend to hover, curate our children's every experience and do just about everything for them. What these kids learn from sledding, other than that it is really fun, is that the fun comes from the hard work of trudging up the hill with your sled. And that the work is actually part of the fun. Worldwide, this is the way most kids live — most kids contribute to their households in relatively meaningful ways, help care for younger siblings, and find their own fun. Only in the industrialized West have we made childhood an idyll of no work, lots of play, lots of toys, and formalized education. While sledding, kids are having a hybridized experience, if you will, a mashup of what childhood evolved for (working, helping out and helping oneself) and what it has evolved into here (playing around).

In addition to the gravity and the mix of work and fun, there's the cultural mix. There are people from everywhere living in Manhattan, and the sledding hills are a place where it shows. Many adults I saw were obviously sledding with their kids for the first time (one kid was wearing sneakers without socks. A nanny from the West Indies almost got taken out by a sled because she was walking up the middle of the hill rather than the sides). Others were just obviously out of practice, forgetting to scurry out of the way once they'd reached the bottom of the hill.

With a bit of coaching from the sidelines (some of us grew up in Michigan and don't mind telling others how to sled — "Hey, walk up the sides, not the middle where the sleds are coming down!"), newbies, the rusty and kids got the hang of it quickly. All were having a blast when we left in the late morning. The kids and grownups formed a small, temporary community on a sledding hill, then went their separate ways for lunch. Perhaps the most talked about artifact of contemporary, metropolitan parenting and childhood on the sledding hill was a bright blue plastic device — The Snowballer — that helps you make snowballs without actually touching the snow with your mittened or gloved hands.