While services like Turntable.fm have turned online DJing into a shared experience, audio manufacturer Bowers & Wilkins is doing the same for your next offline party with their Zeppelin Air app. The free iOS app features collaborative playlist building: once you start playing tracks, your friends can join in and add any of the music on their own devices to the mix — though you still retain veto authority. Even better? It all streams live to any AirPlay-compatible device, so you can start spinning without shelling out for one of Bowers & Wilkins' pricey accessories.