Green beer could do it. So could eating asparagus. Here's a link that list the causes of different color pee... can't say how accurate it is:


http://www.school-for-champions.com/health/urine_color.htm

This is not like the question - How does the elephant hide in the grass?? Right??

I dunno, but at least this year, my pee has always had at least a very light tinge of green.