The spiedie is a regional food product that can (to my knowledge) only be found in and around Binghamton, New York.
A typical spiedie consists of marinated cubes of meat which are grilled on a skewer and served on a slice of white or Italian bread (note that spiedies are not usually served on rolls). The eater takes the skewer full of meat, folds the bread around the meat, and pulls out the skewer, essentially creating a sandwich of little hunks of grilled meat.
Local theorists claim that spiedies originated in Italy, the name coming from the Italian word "spiedo" (which means spit). Some people credit the spiedie to Augustine Iacovelli, who immigrated to Endicott, NY from Italy in 1929. In 1939 Iacovelli opened a restaurant which served lamb that was sprayed with a sauce made of vinegar, water, lemon juice, garlic, and mint, and then cooked on a skewer. Today spiedie meat is marinated for at least 24 hours prior to cooking, and can be found in lamb, chicken, beef, and pork varieties. Chicken seems to be the most popular spiedie format.
People who grew up within the sphere of spiedie influence seem very enamored of spiedies. Everyone has their own version of spiedie marinade, everyone has their own favorite spiedie restaurant, and it is terribly important that anyone who spends significant time in the area be introduced to this local phenomenon. The spiedie is even celebrated in an annual "Spiedie Fest and Balloon Rally" held at the Tri-Cities Airport in Endicott. Frankly, their spiedie ardor is a bit disturbing -- it is, after all, only a sandwich.
Personally, I am convinced that there is some connection between Binghamton residents' intense love of spiedies and the development of 'The Twilight Zone' by Binghamton native Rod Serling. Unfortunately, this is a laughable, unimportant conspiracy at best.
For more information about spiedies, see http://www.geography.ccsu.edu/harmonj/atlas/spiedie.htm