Rap enthusiasm site, Rap Genius has gone through the impressive tasks of combing rap and Google Maps. Rap Genius' Rap Map is a Google Map-based visual almanac of all things rap. You can scan an area and view rap landmarks and places mentioned or referenced in some famous rap lyrics.
The Rap Map doesn't just cover major cities and famous rap locations like Atlanta and New York. A quick scan of Paris turns up some interesting information as well.
This is definitely one of the more entertaining Google Maps mashups. You get kind of caught up in it like you would with Wikipedia (admit it, you never stop at just looking up a movie). It's currently uncertain if Rap Genius plans to expand on Rap Map, adding more features and more information. I would certainly be interested to be able to sort by artist or area or maybe have it jump around, randomly, presenting me with rap trivia. As strange as it may sound, there's lots of room here for this to get more interesting over time.
Now where's the equivalent for other genres? Maybe Pitchfork could roll one out for rock? And for as many stories as there are in country music, CMT would have plenty to include in its own twangified version of the rap map.