A former destination for aspiring fighters and children seeking refuge from gang violence, Joe Frazier’s Gym is now a discount furniture store. Dennis Playdon, an adjunct professor of architecture at Temple, noticed the “For Sale” sign on the building last year. “It occurred to me this was going to be an endangered building, and Joe Frazier’s Gym shouldn’t be lost,” he said. Playdon and his students are now working with others to get the building listed on the National Register of Historic Places.