Finally, the fuel-cell powered mp3-player is ready.

Toshiba has released a prototype of a mp3-player that plays 35 hours of music with 3,5ml of Methanol. It shall be released in 2006.
Now, think about Laptops and other Gadgets that finally will be operational for a reasonable amount of time!

Now, think about a colony of bacteria, yeasts and algae on your roof that will produce the neccessary (m)ethanol by the power of the sun!
Hard to believe? The department of Biotechnology (where I study, actually) has a working prototype on the roof that produces not too much ethanol yet but 3,5ml per week are definitely possible!
And making Methanol from Ethanol is a piece of cake.

Click the picture here for details:

http://www.biotec.rwth-aachen.de/english/bioenergy.htm