When I first came to Pittsburgh, I loved the Original Hot Dog Shop, or the 'O' as it's called. You have to try the O-fries...just get a small because they're ENORMOUS! We walked in and order 2 larges for several of us once (before we were familiar with them) and everybody in the shop stopped what they were doing to gape at us. (fortunately, we switched to 1 large which was still WAY too much food). The O is nice and cheap. Unfortunately, I seem to have exhausted my tolerance for their food because just the smell of their fries make me queasy now. It's worth the experience if you've never eaten here before, though. There's one in Oakland on Forbes and one in CMU's UC.