Ever since I heard about Prolog, I wanted to try out the so-called Einstein Puzzle in it.
So, after finishing the Prolog chapter in Seven Languages in Seven Weeks, I tried to make as clean an implementation as possible ("Just state the rules, and you'll get a solution").
It's... not far from truth, to be honest. The auxiliary functions are a bit funky, but the truth is that the program is about as concise as advertised.
See also: The solution that I worked off of, after I requested some assistance on IRC, written by Eazar