https://www.sfgate.com/sf-culture/article/green-day-surprise-show-22154123.php
As fans streamed out of the exit of the venue, they realized the show wasn’t quite over — an enterprising East Bay punk band called Stay Out set up with a generator outside, shredding through songs and giving out free CDs. It made for a DIY encore to the show that would’ve certainly gotten the Green Day stamp of approval.