Google is very keen on Easter Eggs, as it's got quite a few of them on its search page and in pretty much all of its other products. Google Maps too has a fair share; some of them are only shown on special occasions.One interesting Easter Egg you can experience for yourself is searching for Philadelphia in the US. The search has to start on the main Google site, not on Google Maps.
Typing in the name works as expected and you get the right results. If you click on the map thumbnail in the search results page, you'll be directed to Google Maps, but you may notice that the query will change to the "city of brotherly love," as Google Operating System notes.
This makes sense, as Philadelphia literally means "the city of brotherly love" in Greek and is one of the nicknames of the city.