Savor the nice weather before the thunderstoms rain on everyone’s parade at Piano Terra. The pop-up restaurant is open seasonally in the north garden of the Art Institute of Chicago. It offers a menu of made-to-order sandwiches and salads. It returns today, for the first time this year, with sandwiches such as the PLT (La Quercia prosciutto, baby lollo rosa lettuce, orange sundried tomato pesto and green olive spread) as well as soda, coffee and tea. Weather Permitting, the café is open from 11:30 AM to 3:30 PM every day until fall.