Yes I have, last year for my Birthday. It is quite a nice place to spend few hours at. You can see the Fan Club - become a member and see the 2 bikes Rossi won his World Championship with. Also the local 7-11 is basically a Rossi shop - everything from lighters to clothes, signed photos and models. Also there are some cute free postcard you can collect
It is quite amazing to go around the village - every house got a 46 flag, even the police car got one there! there is a small coffee shop which is all about Rossi - books, mags and good coffee
It would really help if you have SatNav with you, since it is in the middle of nowhere!
Again - few hours for Rossi's fan would be nice, don't count on a whole day there though.
Enjoy!