Joseph Gordon-Levitt has said via his Twitter that he and Zooey Deschanel are making a short dance film along with the director of 500 Days of Summer.  To quote:

Me and Zooey making new short dance film (by Marc Webb of 500 Days of Summer), coming soon to Internets near you!

He also attached this funky picture.  Click it for a larger view.

Related posts:

1. Is JOSEPH GORDON-LEVITT the best young actor in Hollywood?
2. Levitt and Deschanel 500 DAYS OF SUMMER featurette
3. Another 500 DAYS OF SUMMER featurette

Joseph Gordon-Levitt and Zooey Deschanel making a dance film HollywoodHubbub