24 hours. They made a 24-hour music video for this song. It's a silly idea, a stunt that no sane person could ever sit through and watch, an exercise in a stunt devised to drum up some virality for a song that needed no drumming up on its own behalf. I've never seen the video, I never will—however, if there's a song you must listen to for 24 hours, "Happy" might be the pick. That hook has been rattling around our heads for something like four years and counting, after all.