Starting August 21st, the Colosseum will be open for night tours (9:00 pm to midnight) until October 2nd. Tickets cost 15 Euros and reservations are a must. Be sure to request an English-speaking tour. For more information (only in Italian, unfortunately) go to pierreci.it or ask your hotel concierge to call the ticket office for you. The Baths of Caracalla will have a similar program through October 23rd.