Time of day to turn on music and get relaxed...; )
At fourtwenty, me and my friends were doing the same thing at the same time. Even if we were all at our own homes.
The time of day when the whole world gets high, similar to the British tea-time.
Also rumored to be the police code for marijuana possession in many major police forces.
There is a famous clock in Cali. stuck on 4:20.
It's 4:20, do you know where your bong is?