Not sure how this one flew under the radar, I would think people would be more excited about the results lol:

http://www.washingtonpost.com/wp-dyn/content/article/2006/05/25/AR2006052501729_pf.html

For those too lazy to click the link and read, here is the highlight:

“The largest study of its kind has unexpectedly concluded that smoking marijuana, even regularly and heavily, does not lead to lung cancer…

“We hypothesized that there would be a positive association between marijuana use and lung cancer, and that the association would be more positive with heavier use,” he said. “What we found instead was no association at all, and even a suggestion of some protective effect.”"

You read that? some protective effect, mauahahahahahahahah……. the iron lung lives on… now we just need a study proving it improves memory! lol