I live in Arlington but work in DC, so I don't often get the chance to stop by the Pupatella food cart outside the Ballston Metro stop. After stopping by today, I'm even more disappointed to not have the opportunity to go there for lunch more often.
I don't know how often they are doing this, but they were offering a grilled steak sandwich as a special. This sandwich was among the best that I have ever had, with great meat, onions, and cheese on a delicous grilled bun.
Quite frankly, I don't understand why there is not a line 20 people deep for this kind of food at this price. If you have a chance, get over there.