In all seriousness, urine is full of nitrogen, if you water it down it's a good nitrogen source, straight urine is too strong and will burn/kill the plant.
Actually in the Marijuana Growers guide by Ml Frank he suggests using urine in a hydro setup, the book is like 20 years old, so there are plenty of better fertilizers to use.
~what i wanted to reply was...
"Piss is awesome for weed, but you have to pee directly on the buds towards the end of flowering, it's also good to do a water cure... Substituting piss for water."
-don't tell anyone you pissed on your plant.