This restaurant chain never ceases to amaze me. I pass two of the establishments with some regularity and the queue lines boggle my mind. With restaurants on all four corners the one on 8th avenue and 44th will have a line half a block long. Can it be that good? Not yet willing to explore with those kinds of calories. But read the write-up below. They say it better than I.
http://en.wikipedia.org/wiki/Shake_Shack