Graz has now posted the Signpost 2007 application that they built for MEDC 2007 online at their website. Download and try it now. Obviously you won't be able to participate unless you're in MEDC right now, but try it anyway.
Unfortunately you won't be able to experience the full application especially the part with the camera, but here are some markers you can test your application with.
One of these markers contain an Easter Egg item.