Link: http://www.ew.com/article/2015/08/01/ghostbusters-cast-boston-tufts-medical-center
This is pretty awesome of them to do!

There wasnt anything strange in their neighborhood, per se, but the folks at Tufts Medical Center in Boston knew exactly who to call to brighten their spirits. The cast of the new Ghostbusters reboot took time out of their busy filming schedule to give patients at the Floating Hospital for Children an other-worldly surprise.
Kristen Wiig, Melissa McCarthy, Kate McKinnon, and Leslie Jones showed at the center in full Ghostbusters attire, proton packs and all. They made the rounds visiting with patients and their families, and posing for photographs. As depicted in one such photo published on the Tufts Medical Centers Facebook page, some of them got to hold the stars ghost-fighting props. Thankfully, no one crossed the streams.
Thank you for taking the time out of filming today to put a big smile on our patients faces! the hospitals post said. You can see the rest of the photos below.
This is pretty awesome of them to do!