The Boogie Board is an LCD-based tablet with a reflective layer which essentially eliminates the need for a power-using backlight. No more paper doodles could mean a few more saved trees per year.
Implications - The Boogie Board isn't something that will take a lot of power, either. The creators say only a "small amount of power" is necessary to completely clean the slate when you're finished with it. It also comes equipped with a watch battery good for 50,000 uses. Now that's a commitment to environmental quality.