We're staying one more night post RS tour 11/11....when I had this great idea I didn't realize it was Sunday...is there anything open for business in Rome on Sundays?? I'm all for cafe's all day and people watching...but if they're closed my tour buddies will be grumpy...
You should be fine in Rome. Monday is often the day for closures. Most things are open, but maybe not super early. Try attending a church service for the experience of it. Make reservations for the Borghese gallery in the morning (it has tickets available on 11/11 for all time slots, including 9 a.m. see http://www.ticketeria.it/ticketeria/borghese-eng.asp#)
The above post is correct. The only thing that will be closed is the Vatican Museum and some shops. You will have plenty of places to visit and keep in mind that fountains and piazzas never close.
Just arrived home last night from Rome. Yes, everything is open on Sunday.