Everyone left. It’s yours for the taking.

GROOVE
Cajun Dance Party
What: Mardi Gras moves to Brooklyn Bridge Park with legit Louisiana Creole (and Grammy-toting) Terrance Simien and his zydeco beats.
Why: Replace your go-to noodling with free dance lessons from Jalopy Theatre and School of Music, while Jesse Lége and Bayou Brew provide traditional Cajun tunes.
When: Tonight, 7 p.m.
Where: Pier 1, 2 Old Fulton St., at Furman St.

SCREEN
Rooftop Films: Dark ’Toons
What: Get sufficiently creeped out by eleven frightening animated shorts while lounging atop a high school in an artfully tagged space.
Why: Stave off nightmares with free drinks that follow at R Bar.
When: Fri., 8 p.m.
Where: Open Road Rooftop, 350 Grand St., at Ludlow St. Tickets ($12) at rooftopfilms.ticketleap.com or at the door.

DISCOVER
Whatnot
What: Up-and-coming designers skip the highbrow, astronomically priced prototypes in favor of objets d’art you can actually use — and afford.
Why: A reusable bag that collapses with parachute mechanics, citronella-scented postcards, and a music box that adjusts to the crowd.
When: Thru June 8. Daily, noon-7 p.m.
Where: The Future Perfect Pop-Up Shop, 2 Cooper Sq., at E. 4th St. (212-473-2500).

SCORE
Assembly New York Memorial Day Weekend Sale
What: The editor favorite marks every last item in the store (and online) 20 percent off.
Why: Leave with bags stashed with the house line, A Détacher, Prism swimwear, and more.
When: Today-Mon., noon-8 p.m.
Where: 170 Ludlow St., b/t Stanton & E. Houston Sts. (212-253-5393).

SAVE
Tracy Reese Sample Sale
What: Pop in for patterned goodness when one-of-a-kind pieces from this season’s collection go for $35-$50.
Why: Unpacking last summer’s wares wasn’t nearly as exciting as you thought it’d be.
When: Today & Fri., 9 a.m.-7 p.m.
Where: 264 W. 40th St., b/t Seventh & Eight Aves., 2nd flr. (212-807-0505).

Lela Rose Sample Sale
What: The Texan designer’s spring runway looks get marked up to 75 percent off, putting them in (closer) reach.
Why: Investment pieces are a lingering to-do on your list.
When: Today, 9 a.m.-6 p.m.
Where: 224 W. 30th St., b/t Seventh & Eighth Aves., 14th flr. (212-947-9204).

Photo: Ac4lt / Flickr