Updated

It might be the cheapest—and most fun date you’ve had in a while. More museums are offering after-hours events and even sleep overs for adults.

San Francisco’s Exploratorium is one of the city’s top family attractions—a museum with hundreds of hands-on exhibits that beg you to pull, push and touch.

But every Thursday night,  the museum is only open for adults 18 and older and on the First Thursday of the month,  throngs of young San Franciscans flock to experience Life After Dark with music, live performances, the chance to hobnob with inventive scientists and designers and of course, the chance to play with all of the exhibits without any kids in tow—maybe even having a meal or cocktail at the museum’s SeaGlass restaurant overlooking San Francisco Bay. Even better, the cost is just $15.

San Francisco’s California Academy of Sciences also hosts Nightlife every Thursday night, where cocktails are served (you must be 21 to enter). The focus might be on the stars—or the sea.

As museums offer evening programming for young adults, they’ve discovered it’s a good way to encourage greater involvement. The crowd that comes, meanwhile, finds these gatherings are a good place to meet people—or bring a date for a different kind of night out that won’t cost a bundle.

Even expensive programs—like the  American Museum of Natural History’s adults-only sleepovers, which begins with a champagne reception, music provided by a Jazz trio and special live-animal exhibition—are sold out through June, despite the cost -- $350 per person

Here’s just a sampling of what’s out there—check in your city at art museums, zoos and science museums:

IN PHILADELPHIA, the Philadelphia Museum of Art has Young Friends who enjoy special tours and activities just for the crowd that’s 21-45.

IN WASHINGTON DC, The Phillips Collection in Washington DC touts the Phillips After 5  the first Thursday of every month with art, live music, food and cash bar often tying exhibitions to interactive performances and events, ranging from music and dance to fashion and performance. Asia After Dark at the Smithsonian’s Freer Gallery of  Art and the Arthur M. Sackler Gallery are often the best art parties around. And for Animal lovers, the National Zoo is just one that offers evening activities nearly monthly. Think Brew at the Zoo (drink beer and save wildlife!)  or coming this spring, ZooFari with gourmet fare from nearly 100 of DC’ s restaurants.

IN LOS ANGELES, the LA National History Museum does "First Fridays  complete with after-hour guided tour, spinning from local DJs.

IN CHICAGO, if you love planetariums, you’ll love Adler After Dark, which includes open museum access, admission to scheduled sky shows, telescope viewing inside the newly renovated Doane Observatory and complimentary snacks and cash bars.

IN ATLANTA, The High Museum of Art  has Friday night s with everything from drawing classes  in the galleries, wine tasting and music.