If you're old enough, you'll remember seeing Ripley's Believe or Not drawings in the newspaper or in paperback collections of a skull with an iron rod driven through it from under the cheek through the top. That skull belonged to Mr. Phineas Gage and it's kept for public display in the Warren Anatomical Museum, at Harvard University Medical School's Longwood Campus. Take the E train on the Green Line to Brigham Circle.
The Countway Medical Library houses the museum. Hours are weekdays 9-5. The Library is located at 10 Shattuck Street, which dead ends at the library's front door and isn't obviously connected to Brigham Circle. When you get off the train (outbound) go straight across Huntington Avenue onto Francis Street. If you cut through Brigham and Women's Hospital, you'll be on Shattuck Street. Take a right and the library will be in front of you. Admission is free.
There are a variety of exhibits, not just Mr. Gage's preserved skull. It's an interesting visit and not something most tourists see. It's not as well publicized as it might be, but then again, this isn't a tourist attraction so much as an institution of higher learning. Afterward, walk around campus. Harvard's Medical School building is impressive, as one would expect. At lunchtime you can grab a pizza. See the list to the left for all the pizzerias in Mission Hill (this neighborhood). We recommend Penguin if you want to sit down and enjoy a good pie and talk about the curiosities in the museum.