In the lucid dream I just woke up from a few hours ago, I had the opportunity to smoke marijuana. My immediate reaction in the dream to getting this opportunity was, "Yay! I can do this without getting in trouble or messing up my real body, and if I do it, I can post about it on the forums!" I was specifically thinking of this thread, too. :)
I have never tried marijuana in real life, so I can't compare the reality to the dream. In the dream, the drug didn't change the environment or make me feel any different. Shortly after I inhaled, the handles of a nearby blue shopping bag started wrapping themselves around my arm, but I wasn't sure if that was an effect of the drug or just ordinary dream weirdness.