There is a huge coordinated exhibit of the works of Ghirlandaio, his family, and workshop going on in Florence and towns around the city (the main installed show is in Scandicci but of course many works are in situ around Florence) until the first of May, 2011. You really need to visit the site to see the list of locations, hours, etc. and there is also a printed map you can find the in the tourism offices in town (I picked one up in the Santa Croce office and would have to assume they have them also at the office near the station and the one by Palazzo Medici) which is very helpful and makes a good long term reference too:
