Marc Webb created a music video as a companion piece to the film , titled " The Bank Heist " . It features Deschanel and Gordon-Levitt dancing to " Why Do You Let Me Stay Here ? " , a song by Deschanel 's folk group She & Him . Webb remarked , " when we did n't include Zooey in the dance sequence in '' 500 Days '' , she was a little heartbroken and I felt like I needed to remedy that . " The film made its debut at the 25th Sundance Film Festival . It proved a huge success and received a standing ovation from festival crowds upon screening . In Europe , '' 500 Days of Summer '' premiered in Switzerland as the opening film of the 62nd Locarno Film Festival
25th Sundance Film Festival
2009 Sundance Film Festival
500 Days of Summer