1st - You guys are going to kill this kid or his kidneys with your suggestions.
2nd - The suggestion to use someone else's pee is from the movies. MOST places check temperature first. This is why you do it at a medical office and not in some dark basement.
3rd - MOST places check for diluted urine and will just ask you to come back if they can't get a reading. This may may not be such a bad idea, but may also reveal to management that "something" was up. They are legally allowed to not hire you for suspicion.
4th - THC is stored in your body fat which is why it ends up in your urine in the first place. Drink lots of water and go sit in a sauna for a few days (make sure you don't take that literally...spend like 10-15 minutes max, per day). It doesn't matter how much you pee, if it makes it to your body fat, no amount of peeing with "clean" you out.
5th - Schedule your drug test (if you can) for later in the day. This is because the urine that stores up in you overnight will be the most concentrated. In either case, make sure you pee about an hour and a half before your appointment while continuing to drink lots of water. This should give you maximum flush.
6th (Bonus if you're not a regular smoker) - THC typically stays in your system for 3 days. BEFORE PEOPLE FLAME ME, this is for a typical non-smoker. If you're a regular smoker, it could take up to 30 days to completely clear (sometimes more). Also, it is not a grantee that it will stay in your system if you smoked a little one night. THC dissipates in about 20 hours if it doesn't get sucked up by your fat metaboloids. Really depends on your metabolism - I.E. if you are one of those super skinny, I can eat an elephant and a small child, body types.
7th (Another bonus if your employer is cheap) - Most employers only require the test for Opiates, Amphetamines and the immediate presence of alcohol. They have to pay more for the THC test.
Good luck! Positive thoughts. Though I never get why people panic so much. It's not like they call the police and arrest you for failing the test.
Good rule of thumb though...if you are unemployed, don't smoke until you are. While I don't buy the brain cell/permanent damage argument, you also don't need to "kick back and relax" until you're taking care of yourself and your responsibilities.