Jimmy Fallon showed up to Marie’s Crisis Cafe, a gay bar in the West Village of New York City, and gave an unsuspecting audience the drunken performance of their lives. He had the whole place sing along to an a cappella version of Billy Joel’s “Piano Man,” then lead the crowd through “Summer Nights” from Grease and his 2004 Saturday Night Live sendoff “Believe it or Not.” Watch below:

Piano Man:

Summer Nights (click here if video doesn’t play):

Believe It Or Not: