Here is a good one for MythBusters. Ontario marijuana users think that they drive better when they're on the weed. M-B did a very amusing and enlightening session on driving when alcohol-impaired, and another crash course on cell phone impaired, so they should weed out the myth conthepthions about marijuana.
The problem is, how long is one impaired on the weed? Unlike booze, which the kidneys will remove from your blood stream in a matter of hours (we don't buy beer, we rent it), marijuana is stored in body fat.
It has a measurable half-life in the body of about seven days. This means that a week after smoking a joint, the level is half of what it was right after smoking it. If you only smoke one each week, you are piling on more and more where you still have a lot in the body. Do that once a week and when do you come to the permanently impaired state?
The Ontario users who think that they drive better are obviously judgment-impaired, at least. How about reflex-impaired? Visually impaired? Life is so good - impaired? Speech-impaired?
Tho, come on Myth-Buthterth, thow us what'th what.