http://www.hightimes.com/ht/lounge/c...bid=313&aid=24

April 20 at 4:20 PM is the "pot-smokers' holiday," also variously described as the "hippie New Year," "national smoke time," "national pot-smoking day," "the holiday," "pot appreciation day," "the ultimate session," or "a day of tribute to the scene." One enthusiastic smoker reported: "Every group has its holidays, and pot-smokers are no exception. April 20th is the day of worship observed by smokers around the world," Another said: "It's comforting to know that hundreds of thousands of other people are lighting up with me on 4/20. It's about the community identity of marijuana-smokers."
Most pot-smokers would probably accept as fact that 420 originated in San Rafael, California with Steve Waldo, who used the expression "420 Louie" in high school. Waldo used it as a secret code to remind friends to meet for smoking sessions at the Louis Pasteur statue, 70 minutes after the 3:10 dismissal. However, whether or not the smokers I talked with actually knew of the veracity of Waldo's claim, it made little difference in their indifference to determining 420's true origin. One expressed the typical view: "The actual meaning of 420, or where it came from, seems unimportant to me compared to the feeling of 420. That is the true meaning." Another was of a similar opinion: "Most people do not desire to know where 420 came from, but rather enjoy it for its cultural importance." A third explained, after reviewing a number of possible theories: "While some of these reports are more believable than others, they all represent how important the number is to the marijuana community." Emphasizing the value of learning from talking about 420, a fourth smoker expressed the general point: "I think the most valid meaning of 420 origins is the underlying things you learn."