Princeton’s first annual Pi Day, celebrating Einstein’s 3-14 birthday, will survive the potential bad weather, we predict, because so many people and merchants are involved. Everything but the pie throwing is inside, points out Mimi Omiecinski of Princeton Tour Company, profiled in this week’s issue of U.S. 1. She worked with the Princeton Merchants Association, the Princeton Public Library and a host of others to make it happen.

And here’s a special shoutout to Joy Chen (shown here) who designed the clever but respectful logo for PiDay, a rumpled portrait of the great man himself with the Pi symbol and a birthday cake. Joy and Earl Chen own the “studio for social expression,” JOYcards, at 6B Chambers Street. They may have a few of the 60 cent buttons left. It’ll make a terrific souvenir. They also offer a one-price discount on all their beautiful cards, even their $10 ones. Each will sell for, you guessed it, the price of the day, $3.14.

The day begins at noon with a signraising for Einstein’s Alley, a private, non-profit branding and economic intitiative for central New Jersey. “What more fitting day for officials to gather and raise a sign recognizing Princeton as a key municipality in the research/technology center that is Einstein’s Alley than Einstein’s Birthday,” says Katherine Kish, EA honcho. The sign will go up on Stockton Street at Lover’s Lane, and there will be parking down the street at Marquand Park.

Stores with banners offer Pi Day discounts, stuff selling for $3.14. In one long block on Nassau Street you can make three Einstein stops: The Einstein museum at Landau’s store, the Einstein souvenirs and artifacts at the Historical Society of Princeton, and the Princeton University store, which offers a 23.14 percent discount on Alice Caprice’s “Quotable Einstein” book and its other books on Einstein.

Then head for the Princeton Public Library: After the 1 p.m. pie judging at the library, help recite the complete string of Pi numbers, led by Princeton University students. At 1:59 p.m. (the next three digits of Pi) the Princeton Plasma Physics Lab will conduct science experiments.

For $3.14 take the Einstein tour, led by six costumed re-enactors, telling about Einstein’s life; you will follow the treasure hunt trail.

Pie throwing on Palmer Square is at 3:14 p.m. (natch) sponsored by PNC Bank and McCaffrey’s which will serve free birthday cake.

Let the party begin.