The well-oiled volunteer network of parents involved in their local PTAs sprung into action after Sandy to put their fund-raising and outreach expertise to good use, often miles beyond the boundaries of their local schools.

There is no centralized accounting of how many New Yorkers owe their livelihood to public school PTAs. But parent association Web sites — which often include lists of the activities parent dollars are now responsible for — suggest that if you are an actress with an appetite for history, an entrepreneurial bongo drummer, a yoga instructor O.K. with teaching downward dog to 6-year-olds, even a skateboard champion looking to earn some extra cash, currying favor with the city’s better-off PTAs is just good business.