>>>http://abcnews.go.com/US/story?id=3045574
>>
>>I just read this too. I thought kids waiting until 4/20 to start killing each other in the schools. Tell ya what - my sister doesn't let her kids goto school on 4/20 anymore.
>
>I know that 420 is a drug reference, but what does it have to do with killing?

Its the day that Columbine High School shootings happened - although with some others since then. I'm sure its listed somewhere here: http://www.urbandictionary.com/define.php?term=420 - as far as the drug reference - ya that's the common assocation with 420 - that started in 1971 by some california potheads.