Tteokbokki is one of the most popular street snacks in Seoul, often being vended by older women in street carts everywhere you go, particularly late at night. Tteokbokki is essentially little cylindrical rice cakes that are cooked in a spicy red sauce, and served on plates with toothpicks for about $2-3. I don't really care for them, personally -- too gummy and too spicy and not much else.
So how are they, you ask? They are surprisingly sweet upon first taste, with a nice crunchiness, like a Dorito. After the second or third one, the heat catches up to the sweet and becomes the main aftertaste. While I don't like tteokbokki rice cakes, I do like the tteokbokki chips. Something about the sweet followed by the spicy just works for me.
If I drank beer, I bet they would go good with one.