Back in 2010 on Chris Creamer's sportslogos.net, a user named Kevinmets posted a logo mashup with elements from various New York sports teams. The thread took off, and designer Dennis Fanning went nuts. He ended up creating logos for almost every major sports city. Would any of these make a good hat or tattoo?
You can check out more of Fanning's design work at fanningcreative.carbonmade.com.