Get free admission to hundreds of museums around the country thanks to Smithsonian Magazine’s Museum Day Live! – this is sponsored by the magazine every year and lets you sign up for free tickets at a participating museum. The key is that you have to register online to get the free tickets, you can’t just show up at a museum.
In Boston the Museum of Fine Arts and the Harvard Museums are included, among others, although I am tempted by the Paul M. Russell MD Museum of Medical History and Innovation. Never been, but it sounds neat!
Here’s the main page with all the details: http://www.smithsonianmag.com/museumday/museum-day-live-2016/