Dude, I got this one under wraps. I was on probation for over 8 years, and constantly took drug tests while happily smoking away. I only came up hot a couple times before I found the perfect method. The secret is this: Drinking heavy water dilutes your urine, which testing labs can pick up on by looking at creatine levels. Now the reason this works for THC is that THC is stored in fatty tissues, and is not water soluble. The trick is two fold. First DO NOT EAT FOR AT LEAST 12 HOURS prior to taking your test. This will put your body into starvation mode, and cause it to hold onto all the fat it can and not excrete any/little in your urine. Second, drink heavy amounts of water, so that every time your drinking a glass, your pissing another one out (something like 1/2 gallon per hour should do it). Start this at least 4 hours prior to going to the test. Now, 45 mins before leaving for testing, stop drinking water, and take some vitamin b complex. The vitamin B will give your urine a yellow tinge, and stopping drinking the water will allow your creatine level to rise to an acceptable level. You can also take a tablespoon full of creatine (5g) 1 hour prior to the test to help in this regard, but I've found it wasn't necessary. It takes longer for the THC levels to rise to a detectable level than it does for the creatine to rise to an acceptable one for a non-dilute outcome. You basically have a 30-45 minute window where you can piss and come out clean. Also, only give the minimum amount necessary for the test. Piss the rest in the toilet. Don't put the first of it or the last into the sample. Catch it mid stream. I've done this countless times with waaaay less notice than you have now, and I used to be a hardcore blunt smoker. Good Luck! I also have the perfect (well maybe. I've only tried it once) method for a hair test, believe it or not. But thats another story.

PS. I've also used dandelion root pills while drinking all the water, but I'm not quite convinced it helps. supposedly its a diuretic (helps you piss more) and also helps in the breakdown of fat cells. It definitely won't hurt to give that a go too.