What are the Origins of ‘4/20’?

The number 420 has become synonymous with all things marijuana, but exactly why is less clear.

Some have said 420 is a local police code for someone smoking marijuana. Others have said it refers to the number of active chemicals in marijuana.

Another idea is that 420 is a nod to Bob Dylan and his 1966 song "Rainy Day Women #12 & 35" which contains the lyric, "Everybody must get stoned." Multiply 12 by 35 and you get 420.

Another theory that I think is a little more solid says that some teenagers from San Rafael, California named themselves "the Waldos" and would meet very day at 4:20 p.m. near a statue of Louis Pasteur to smoke joints.

A website that claims to be associated with the Waldos declares them to be "The Founding Fathers of 420," although it doesn't appear to be current.

So where do you think it comes from??