For many in New York City, the Friday after Thanksgiving is a day to digest turkey, jostle with shopping hordes  and curse the fresh parking tickets tucked beneath untold thousands of windshield wipers.

Every year, a sleeping army of New Yorkers and their out-of-town guests forget that Friday is not a holiday and fail to move their cars for street cleaning. But the city does not forget: Traffic agents give out parking tickets furiously, more than three times the number on a usual day. The post-Thanksgiving bonanza of roughly 20,000 tickets is worth some $900,000 to the city.

But not this year.

Because of a quirk of the calendar, Friday was a city-recognized holiday after all: Id al-Adha, a Muslim celebration. Alternate-side-of-the-street parking rules were suspended through Saturday, giving New Yorkers one more reason to offer thanks while depriving the city of hundreds of thousands of dollars.

The intersection of American tradition, Islam’s lunar calendar and the street-cleaning schedule made for a peculiar holiday mash-up that pleased car owners and imams alike. “On Id day we share the blessings with all New Yorkers,” said Imam Shamsi Ali of the Islamic Cultural Center in Manhattan. “The blessing is that they have the opportunity to have free parking.”