LSD is a collaborative VJing webapp. It allows people in the audience to control the visuals projected on stage at concerts and festivals, all using their smartphones. They can mix together video clips and add effects, all in real-time by connecting to the LSD website when at a concert.
For this hackathon, I added support for crowd-sourced visuals from the audience's phone cameras using Tokbox. Now in addition to using the supplied video clips, any audience member can send a live video feed of what they are seeing to the big screen, and even mix together multiple video feeds from several audience members at once.