Any unpleasant, unidentified smell or odor, usually in the context of an enclosed area. Flatulence may or may not be involved.
A Dave Letterman catchphrase from the mid-90's.
I walked into my office the other day and was greeted by an unbelieveably awful and not-readily-identifiable smell. I asked, "Whoa, damn! Is somebody frying bologna?" Turned out is was one of my co-workers, who had forgotten she was cooking a Healthy Choice meal in the mircowave, and it was burning (badly).
Walked into a Starbucks last month and smelled something funny (in a bad way). I mumbled alive, "Man, Jesus, is somebody frying bologna?" Apparently the guy at the table next to the door had been lettin' 'em rip for 15 minutes after drinking the new Chantico beverage.