My group will be landing in Florence late on Saturday afternoon. We will want to get acclimated to the city on Sunday. Can anyone recommend things to do on Sunday in the city? Thanks.
In Florence, Monday--not Sunday--is the day when most of the biggies (museums) are closed.
Simply walk around and take in the sights. Do a little window shopping and get your bearings. The museums should be open, but the churches will have limited tourist hours of operation.
Adding to my first answer: There are some Sunday closures or partial closures: The dome of the Duomo (going up to the top of the dome) is closed on Sunday. And the Duomo Museum and interior of the Baptistry close early on Sunday. And some sights are open only in the afternoon on Sunday. Rick's book Florence & Tuscany has a list of these.
Absolutely just walk around and take it all in. There is so much to look at in a stroll through Florence. As you heard, most things are open Sunday, but some of the biggies are closed on Mondays. A couple of Monday alternatives are the Orsanmichele museum (not the church, but the museum on the primo piano - free and open only on Mondays), the newly reopened Bardini Museum (just over the Ponte alle Grazie), and a visit to the Badia Fiorentina near Piazza San Firenze (which is pretty much always open but they request you visit on Mondays).
Also the Tramvia makes its first run on Sunday morning - from the station to Scandicci - so if you want to see a real Florence suburb... :) I think the ride is free also -