By ELLEN TUMPOSKY – abc News

At 4:20 p.m. today—in whatever time zone they happen to be in—pot-smokers will be lighting up to celebrate an unofficial holiday whose origins are debated by stoners with time on their hands.

Does 420 refer to a police code for illegal marijuana use? Is it a veiled allusion to the number of chemicals in cannabis? Or maybe it’s teatime in Amsterdam, the global spiritual home of marijuana smokers. Don’t forget that April 20 is Hitler’s birthday, so that must have something to do with it.

And how do you spell this holiday anyway—420, 4-20, or 4/20? [Read More]