I found this idea for genrating Hydrogen from urine to be quite intriguing..
http://news.yahoo.com/blogs/sideshow/urine-powered-generator-unveiled-international-exhibition-234718329.html
QuoteSo how exactly does the urine-powered generator work?
•Urine is put into an electrolytic cell, which separates out the hydrogen.
•The hydrogen goes into a water filter for purification, which then gets pushed into the gas cylinder.
•The gas cylinder pushes hydrogen into a cylinder of liquid borax, which is used to remove the moisture from the hydrogen gas.
•This purified hydrogen gas is pushed into the generator.