Mary-Kate Olsen at Studio in a School Gala | Pictures

Mary-Kate Olsen hit the town in NYC last night to attend the Studio in a School's 35th Anniversary Gala at the Seagram Building. Mary-Kate supports the Studio in a School organization, which brings creative adults into NYC public schools, day care centers, and community organizations to increase children's exposure to the arts. Mary-Kate didn't have her boyfriend, Olivier Sarkozy, on her arm at the event, but she did mingle with friends like Vera Wang, model Jessica Hart, socialite Stavros Niarchos, Girls star Jemima Kirke, and art dealer Vito Schnabel. Over the weekend, though, Mary-Kate and her French boyfriend, Olivier, were out on the town for a lunch date with her twin sister, Ashley Olsen.