When in Rome, do as the Romans, goes the saying. And what do the Romans do when they are in a hurry and want to have a roadside snack? Simple, choose "pizza and mortazza", pizza bread with bologna in other words. You can delight with this particular street food while wandering between a monument and the next one because in Rome every self-respecting bakery serves this specialty.
A piece of pizza that is very crisp, split in two to make room for fresh cut bologna. It's cheap and it is very good, especially if accompanied by a well-chilled beer.
Those who visit the historic center must call in to the Antico Forno Roscioli for a gourmet-style pizza and mortazza. Or you can enjoy the thrill of following the three-wheeled pick-up truck Pizza and Mortazza, which moves to a different part of the city every day.
To find out if it is in your area take check out their website or simply follow their movements on twitter.
If it is evening and you have been dragged into the nightlife of San Lorenzo, the neighborhood a short walk from Termini station where the students crawl between pubs and clubs) go straight to the Piazzetta, opposite the market. It's a pizzeria take-away open until late which also serves cocktails at popular prices.
Eye on the time, however, on weekends pizza and mortazza always comes around midnight...