Source of an ad hoc wireless signal - how do I identity/find it?

I'm sitting in a coffee shop connecting to wireless with my laptop. I'm connected to the coffee shop's secure wireless network, but scrolling down the list of available networks, I saw one ad hoc connection (WPA-2 personal) with a really interesting name (it's the name of a really rarely known foreign song). I am really curious to find out who is the owner/source of this signal.... Is there a way to figuring that out without yelling across the coffee shop???