I have long loved google maps more than its competitors (though MSN's LineDrive is really cool). One thing I've always wished for is a way to avoid areas you know are slow at a certain time of day, or take a side trip, etc. Well, Google came through for me. Now, you can just drag the line on the map, and it will map a new route with leaving the road before where you grabbed and going where you dropped.
It took a second to change poor directions to my mom's house to the better way. Thanks Google.
Google Maps New Features