Here is an idea, why don't people make games from Wikipedia Public domain Pictures. You could link them together for a story. I was trying to do that but in the end gave in, but I am sure someone could do it.
*cough* *cough* (http://www.adventuregamestudio.co.uk/yabb/index.php?topic=33176.0)
Well, for starters, there's preciously little public domain on Wikipedia. Nearly all of it is licensed in some particular fashion - GFDL or CC-BY-SA usually.