Horst Hörtner was at the Oslolux 2013 where he was talking about Spaxels. Smogdog has summarized his lecture in one picture and it’s absolutely great. On the website of Oslolux you can find a summary of a full conference, it’s amazing how you can show all the topics in one picture, great work!
As a reminder: Spaxels are quadrocopters flying in formation and can be used for real-time-3d-visualisations, for example to show what buildungs might look like at their projected place, or you could build an huge flying 3D-screen, if you have enough quadros. They are close siblings of the Quadcopter Dance Ensemble which specialises on events and performances.