Filthy McNasty's was a club on the Sunset Strip owned by the McNasty Brothers, German immigrants who changed their names when they arrived in America. The club opened in the 1960s and was rebranded as Central in the 1980s, and the Viper Room in the 1990s.
The sweatshirt is great, but the image on the website needs to be updated. A short sleeved shirt is shown and I think that led to confusion with my initial order.