You can find the following trick useful if you are using Google Earth to plan your bicycle trips and you want to have a good idea how steep your journey will be.
Using standard Google Earth projection, this is not very clear (click for large version):
However, you can go to "Tools / Options / 3D View", find a box called "Elevation Exaggeration" and enter maximum possible value here (currently 3.0), instead of default 1.0. The effect is that elevation is now exaggerated to 300% of the original and you can rather clearly see how difficult the journey will be (again, click for large version of the same part of the globe):
P.S: If you have really good brakes, your bicycle can stop on the spot while your body continues moving forward. Hilarity ensues!