This sounds like fun:

Space Child Adventure Grand Odyssey, an animated film showing at the Aichi Expo 2005, has a very special star - you! Visitors to the Mitsui-Toshiba Pavilion get a high resolution digital full-face scan; these faces are edited into that performance of the "film" in real-time.

Every person who enters the theater gets a role; a Toshiba supercomputer inserts the necessary information and presents the one-time-only film. At a recent showing reported on in the TimesOnline, a grandmother in the second row was surprised to discover that her screen persona was a space commando, barking out orders to a squadron that comprised her daughter-in-law and a young couple in the fourth row.

I bet this technology shows up in the gaming world pretty soon.

(via Kurzweil AI)