You've examined the crime maps, scouted out environmental disasters, sought out a good coffee, compared bus routes to real-time traffic, and checked the weather. What else is there to do with Google Maps? How about a game of Risk?
GMRisk is the classic wargame, but uses Google Maps as the playing board. It's more of a "hey, look what we can do!" than a really usable game, at least for now (no AI, opaque interface), but it is suggestive of the varied ways in which online mapping systems like Google Maps and Yahoo! Maps can be used.
As we continue to play with the idea of building a good global environment sim/game, the idea of using online maps as the base of play is definitely something we'll keep in mind.