Just got back from Rome and found that Line A, due to the construction of a new line C, that the line closes down at 9:00 p.m every day, except Saturday. This will continue until April 2012. Arrived into Termini at 11:45 pm from Naples to find that the line was closed but they were running buses from outside in the square "somewhere". Didn't want to wander around trying to find the correct bus, so I spent 10 euro (5.80 euro just to get into the cab with the evening surcharge) to go the distance of 2 metro stops. So, I would suggest that travelers plan accordingly.