"No hot dogs here," the guy manning the cart said.  "I sell wurst, not hot dogs."  And that he does.  Bratwurst, Knockwurst, Alpenwurst, Currywurst, Hungarian Kielbasa and a few others.  You get them whole on a bun, or cut into slices

Not only wurst, it's pretty much a full German restaurant.  Red Cabbage.  Sauerkraut.  Potato Pancakes.  Lentil Soup.  And one or two other daily specials.

There's always a line, no matter what time.  But worth the wait.  There are a couple of Hallo Berlin restaurants too.