"Genius Hour" or "20 Time"

In class last night, I heard about an interesting educational innovation called "Genius Hour" or "20 Time."  Based on Google's philosophy of providing employees with the opportunity to work on their own endeavors/projects for a certain portion of their work time, this educational approach sounds intriguing.  I'm interested learning more about this educational innovation.  Students often come up with incredible projects they would like to explore.  

Has anyone tried Genius Hour or 20 Time in an educational setting?  If so, how did it work?  What were the results?  Did the students enjoy it?  How was it funded?  Did you use any criteria or provide any structure?