For restaurants you have to be a bit more specific (price/style).
There are some pop up close out places around the city center that seem to come and go and offer highly discounted stuff but it's a bit more disorder than I can take. Sales are officially twice a year and so unless you're there in January or June it can be tough. There is a near-ish outlet in Serravalle that I have not been to that you could check out.
For a half day off my favorite museums are the house museums (Poldi Pezzoli, Bagatti-Valsecchi etc.) see here:
https://www.milanmuseumguide.com/col...istoric-house/ and click around for a lot more.
Walking around in the fashion area (Quadrilateral, Via Montenapoleone etc., see here:
http://www.italia.it/en/travel-ideas...ella-moda.html) is an experience as are the Galleria and the Duomo.
The Castello Sforzesco has interesting museums inside an amazing structure.
On the more modern side, Corso Como/Porto Nuova and the near by new buildings are an interesting place to walk around (
http://twistedsifter.com/2016/06/ver...-boeri-studio/ and
https://delightfullyitaly.com/2014/0...-nuova-eataly/ )