I'm personally a huge fan of the smoking scenes in Harold and Kumar. More specifically when H&K are sitting on the couch blitzed out of their tree and that really awful drug ad comes on.

Kid one: I'm so high...I can do anything. *puts gun in mouth*

Kid two: (think of the worst most wooden acting possible and multiply that by a thousand) Nooooooooooo....

*Kid one shoots himself*

MARIJUANA KILLS

Great stuff.