Assemblies were the best part of school. Now, one is becoming its own arts venue.

For anyone who grew up attending public school, assembly days were always a highlight. It never really mattered what the occasion was — a pep rally for the football team, a preholiday film, a giggle-ridden sex-ed lecture, an awkward performance by nervous classmates — what was important was the welcome chance to escape the doldrums of the classroom for a few hours.

On Thursday night, Atlas Obscura will present its own twist on the school assembly, in keeping with the online publisher's interest in offbeat and forgotten places. "Assembly: Underground Films and Philly Legends" will present an evening of short films, archival footage, lectures, and art installations at the Bok Building, the former South Philly vocational high school repurposed as a workspace for small businesses, nonprofits, and artists. "Assembly" will take place in Bok's art deco auditorium, a rare opportunity to see the space in its current form before planned renovations take place.

"The Bok Building has a long history and now has taken on this new life," says John Pettit, head of Atlas Obscura's Philadelphia chapter.  "The space will feel familiar to a lot of people who attended high school in the city, even if they haven't been inside the Bok auditorium: the architecture, the smell, the seats."

"Assembly" will feature several takes on Philly film culture from a variety of perspectives: Jay Schwartz of Secret Cinema will project a rare short film made by University of Pennsylvania students in 1967 and share the story of his eccentric collection of ephemeral films; Brendan Lowery will discuss his "Peopledelphia" Instagram account, which documents Philly's everyday residents; Sarah Biemiller, associate director of Temple Contemporary, will share footage from a documentary on Symphony for a Broken Orchestra, the recent project to save and repair the School District's thousands of broken and unplayable instruments; and location scout Nick Carr will present clips of iconic Philadelphia film locations alongside new photographs of the sites.

"The event is celebrating film and visual culture in the city," Pettit says. "We tried to think of different ways to represent the past, the present, and the future, so we're using different formats: everything from Nick Carr, who's engaging in film in the city through footwork, to Jay Schwartz, who's projecting things on a 16 mm projector, to people who produce media now on their iPhones, all engaging with the space and the city as a whole."

If a school assembly isn't nostalgic enough, visitors will also have the chance to walk into a surreal reenactment of a high school dance courtesy of Klip Collective's Ricardo Rivera. In a new installation piece in the boys' gym, Rivera is creating an immersive environment complete with disco ball, streamers, and video projections that draws on the history of Bok (where Klip Collective is a tenant) as well as on personal memories. As Rivera says, "I'm using the elements of your typical high school gym dance and making it a little more psychedelic and crazy."

It's not the first time Rivera has created an installation piece inside Bok. As part of Thursday's program, he'll discuss his ambitious earlier work "Vacant America," which took over the girls' gym with artifacts, projected names and images from past yearbooks, and audio interviews with a former gym teacher to haunt the space with its own past.

"It was really powerful to see the names and faces of the people who went here over the years," Rivera says  while addressing the gentrification arguments that have surrounded Bok since its reopening. "I wanted to create a monument to the school to open that dialogue while creating a spectacle that showed that we're sensitive to what happened here."

According to Larissa Hayden, Atlas Obscura's deputy director of events,  "Assembly" is in keeping with the site's mission of uncovering unknown and obscure places for both travelers and the city's own residents. "We believe that there's always something new to discover, whether it's around the world or around the corner," Hayden says. "We were founded on the idea of helping people connect with the places where they are. You could live in Philadelphia for two years or 20 years and hopefully we can still surprise you with the people, the places, and the perspectives that we're sharing."