According to a latest Japanese IT news report, it is revealed that the Pentax K-r actually had a hidden function of "Photo Challenger" mode which could be activated via an advanced (at its time ;-)) IR data communication mode with another compatible camera,.
(Credit: Japanese Cameota blog)
After linking up with the other camera, two photos can be selected for comparison and the computer will give marks to the photos in three aspects. The loser will have his photo displayed in a cracked glass window at the end.
A demo YouTube video could be found below: