HTML5 Rocks has a nice tutorial about how you can turn a Google Map into an interactive globe using CSS shaders.
The effect is really cool. Unfortunately most browsers don't yet support CSS shaders. To view the demo you will need to view the tutorial in Google Chrome and to enable CSS shaders.
The tutorial includes a neat video that highlights some of the possibilities of using CSS shaders. Many of the examples demonstrated in the video use css shaders to add visual effects to Google Maps.