Well, the short answer to naru's question is "Yes" -- you
can drink your own urine, it is not toxic, and in fact urine therapy ("shivambu") is an
ancient and respected practice in India. Even
some Westerners have jumped on the bandwagon, although actual evidence of health benefits is ambiguous at best.
However -- will you get high from drinking piss? Probably not (unless it's the kind that comes in big bottles labeled "Guinness"

). Most drugs are pretty much fully metabolized into inactive compounds by your liver and kidneys before being excreted in the urine. As other posters have mentioned,
A. muscaria, the mushroom known as "fly agaric", is a conspicuous exception, and Inuit shamans have practiced piss-drinking to stretch out their supply.
Drug tests, in general, are looking for
metabolites or other tell-tale signs of drug use in urine (such as ketones), not the drugs themselves. I would not count on being able to get high, not even from Keith Richards' urine. But by all means let us know how it turns out.
Quite a few folks in this thread need to unknot their panties. Drinking urine doesn't sound pleasant, and is culturally verboten in most parts of the world, but it's a damn sight healthier and safer than IV'ing heroin (for example). And narutokun, whatever his issues, is definitely not a troll by any reasonable definition of the term.