4:20 was the designated time for a small group of smokers at San Rafael High School in California to meet at a specific location and light up. The number originates some time around 1971. It has since been adopted by smokers the world over as the "universal time to get high."
The original story:
A small group of kids in high school used to meet up everyday after school at 4:20 and smoke on the hill. One day on April 20th, at 4:20 they were all like "woa...it's 4:20, and 4/20- we should make this celebration official" the celebration spread and now 4/20 is an amazing day to get blazed thanks to a group of high school kids from norcal from the 70's
2. A way of mentioning marijuana in the presence of authority figures so as not to get caught.
"I had encountered at least one of those curious mirage-plants about which so many of our men told stories. Anderson had warned me of them, and described their appearance very closely—the shaggy stalk, the spiky leaves, and the mottled blossoms whose gaseous dream-breeding exhalations penetrate every existing make of mask...Although everything was spinning perilously, I tried to start in the right direction and hack my way ahead. My route must have been far from straight, for it seemed hours before I was free of the mirage-plant's pervasive influence. Gradually the dancing lights began to disappear, and the shimmering spectral scenery began to assume the aspect of solidity. When I did get wholly clear I looked at my watch and was astonished to find that the time was only 4:20. Though eternities had seemed to pass, the whole experience could have consumed little more than a half-hour."
It was 4:19, just about that time. i.e., almost 4:20
They pulled out the binger and I started to drool.
It was the five-foot caustic weapon crystal, too.
I caught the fumes and I lost my mind,
Happens every time that I smoke the kind."
-Wasting Time, by ALO
"Alright man! Wait. How the fuck are we gonna make up that early?"
"Oh shit. Fuck. Uhhhhhhhhhhhh. Shit. Oh! I got it! I'll set an alarm!"
"Dude, that's some fuckin' Einstein shit right there bro!"