Here's some serious evidence of how marijuana has gone mainstream. Even giant corporations are now celebrating 4/20.

If you don't know, April 20th is known as "4/20," the unofficial weed holiday. "420" became part of weed culture thanks to a group of stoners in California in the '70s who would meet at 4:20 P.M. every afternoon to smoke.

And this Saturday, some legit businesses are getting in on 4/20.

Pizza Hut is targeting the stoner market by offering their Hershey's Triple Chocolate Brownies for $4.20 on Saturday. These AREN'T weed brownies.

Read more at Time / Chewboom.

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