Some weeks you won't remember the last time you actually walked into a building to buy food. In many urban, corporate centers, all you need to do is step outside the office and you'll be greeted by rows of food trucks offering every lunch option you could possibly desire. As you become a food truck connoisseur, you will start following your favorite trucks on Twitter and mapping their routes. Sometimes a favorite truck will relocate to the other side of town for a while, and you'll alter your planned route just to pay a visit to your favorite restaurant on wheels. Just remember, these things are mobile, and sometimes they will move to a spot far beyond your reach. When this happens, it's best to set your favorite truck free, lest you become a foodie Captain Ahab, obsessively plotting ways to find that lost food truck that has moved on to greener pastures.