John Hutchinson pointed us to this hack a day post about a new projector calibration system. Skip to minute 3:00 in the video to see the applications for multiple projections and non-rectangular, curved surfaces. It uses embedded light sensors in the projection surface and software — no projector hacks — and was created by researchers at Carnegie Mellon (pdf), Stanford, and Mitsubishi Electric Research Labs. Not only could this be a huge timesaver for groups like the Circus of Now, the time saved could be used to get really ambitious and experimental with your projection design.
Ed. Thanks to John Hutchinson for the tip!