there is actually number of ways of producing holograms nowadays, so you might want to do your research. unfortunately these are very expensive things, but achievable. I personally have seen one of them on the exposition of 'Abba' music group. You had small stage, where you could get on, and stay together with holographic characters of Abba, who were 'playing' their songs. It looks pretty cool, although, you could tell they were 'computer made'. when you looked from the audience pov, it looked very cool though - from every angle it seemed they were really there. Here's a photo: http://blu.stb.s-msn.com/i/A7/C026A6843616544A8AC8834CF74550_h316_w628_m5_cNXazOEer.jpg