http://mashable.com/2007/07/11/google-maps-mashups-2/

This site is called mashup for a reason. It mashes google maps with another function. For example one map can help you plot your trip in a taxi in New York and also help you calculate the cost. Another map also shows you places available for rent in major cities. These mashes can save time and money if you go ahead and prepare yourself for a night out or house hunting. There are more mashes though!