29-31 May. Thirty of Milan's old farmhouses (cascine), many of which have been specially restored for Expo2015 are opened to the public. If you miss them this weekend most of them will be open until Expo closes at the end of October.
One of the events (the full programme is still in the making) is a walk from Piazza Gabrio Rosa, through the Parco Vettabbia, stopping at four cascine, the abbey and the village of Chiaravalle, ending at the Cascina Corte S. Giacomo.
For the full programme see the Associazione Cascine Milano website.