I bet this will be one of the most popular Google Maps Mashup: BeerMapping.com
A true Beer lover, the owner of the website has done the hardwork of cataloging the best US breweries, beer bars, pubs and beer stores online & porting them on Google Maps. Currently, I can see 25 US Cities with classifications as Brewpub, Brewery, Beer Bar, Beer Store & Homebrew Store.
There will be more of these coming up by others, like one for UK, then one for Wine & Wineries.
hahaha that’s AWESOME! i wonder if you can overlay that with this one that tracks demographics like where are the single people are – http://blog.fortiusone.com/2006/11/09/geoiq-release-heat-maps-for-google-maps-virtual-earth-yahoo-maps-and-more/