FREE events this weekend in New York City

Downtown Literary Festival

Calling all you literary Gothamites, out there. Here’s your chance to join two iconic Big Apple book stores to “celebrate the literary culture of downtown New York City” at this year’s Downtown Literary Festival, a joint venture of Housing Works Bookstore and McNally Jackson. You’ll have to check the festival’s website for specific events, times and locations (one of the two shops), but come ready for literary advice from authors, signings, discussions and more. Don’t miss “NYC Through the Decades” (4 p.m. at Housing Works), a new event dedicated to focusing on a single decade in the city’s literary culture — the 1950s this time around. Hitchcock’s “Rear Window” will be the focus for David Gilbert, Amor Towles will discuss Robert Franks’ “The Americans” photographs and David Goodwill will talk about Delmore Schwartz. (Sunday, 10:30 a.m.-5 p.m., FREE, Housing Works Bookstore, 126 Crosby St., McNally Jackson, 52 Prince St.)

‘Mathemagic with a Deck of Cards’

It might seem like magic, but much of the trickery behind some of those astounding card tricks that amaze you is rooted in math. Stop by the MoMath museum tomorrow for this edition of Family Fridays, featuring mathematician Colm Mulcahy, who will reveal the mathemagic behind a simple deck of cards. (Friday, 6:30 p.m., FREE, 12+, registration required, National Museum of Mathematics, 11 E. 26th St.)