After my post 2 weeks ago about the use of split screen, I received another example from Straighty 180, a production company in Sydney, who made this music video last year. On the first level it’s just a normal, narrative music promo, but part of the concept was a website where the original video would play splitscreen with another video, together revealing more about the storyline.  
Not as interactive as the Pop Levi experiment, but nevertheless a pretty interesting example of cross-platform approach, still quite rare in music video land.