Atlanta's Sweetwater has been brewing its 420 Extra Pale Ale since 1997. The company also has a brand called Dank Tank and hosts a music festival around 4/20.
Lagunitas, based in Petaluma, California, doesn't have a 420 brew but has been known to use the stoner-friendly number in association with part-time brands like The Waldo's Special Ale, a.k.a. Waldo's 420. A group of friends who attended San Rafael High in the early '70s, "The Waldos" are credited with creating 420, which is a code for smoking marijuana.
On July 8, Lagunitas received a cease and desist letter from Sweetwater claiming they have a federal trademark on the number 420, and asking Lagunitas to no longer use 420 with any of their brands.
"For da record, I'd never call a beer 420 anything - just stuck it here & there, sometimes hid it," Lagunitas founder Tony Magee tweeted. "No problem, I think we outgrew it anyway, but it is what I do. Hope you do too. Long live the Waldos."
In the past, Lagunitas was rebuffed by authorities when they tried to name a brand Kronick. Instead, they sarcastically renamed the Copper Ale to Censored.
Lagunitas also hosts a live music series called Jam in the Van.