I bought the tickets for a ghost tour through Living Social (which essentially got me 2 tickets for the price of one) back in July & scheduled it in August. It's pretty low-key & history-based, but a cute event. (Apparently there's a competing tour group with costumes, drama, & made-up stories.)
Per the website --
http://www.cambridgehaunts.com/ -- it's based on Sam Baltrusis' book GHOSTS OF CAMBRIDGE: HAUNTS OF HARVARD SQUARE & BEYOND (which in turn is a Haunted America book), but there was some additional material that was tour-only (specifically Jolly Jane Toppan, the Sumner-Brooks Affair [detailed while standing in front of Sumner's statue], and the mad bell-ringer of Lowell House, none of which appear in the book). I know this because I bought & read the book last night.
Allow me to elaborate a little on Jolly Jane and show you some pics...
Jolly Jane Toppan (so named for her energetic & friendly demeanor), Cambridge's own serial killer, murdered folks from 1885 to 1901. Her specialty was the overdose as she was a nurse at Cambridge Hospital and Mass General, but she also poisoned many of her victims. After getting caught, she confessed to 31 murders (although those were just the ones whose names she could remember; she killed at least an additional 12 people whose names she couldn't remember, bringing her total to 43).
Given her actions, I can't imagine her hiding anything in terms of more victims, but THE BOSTON GLOBE inflated the numbers to over 100 back in the day... as newspapers are wont to do.
She was caught in 1901, after poisoning 4 people in one family (her greatest regret); she was tried and found unfit. Thus she was committed to the State Lunatic Hospital at Taunton, where she died in 1939. In the best kind of ironic twist, Toppan died of starvation when she stopped eating. She was convinced the doctors and nurses at the Asylum were trying to poison her.
I'm oddly creeped out by her.
More at her Wikipedia page:
http://en.m.wikipedia.org/wiki/Jane_Toppan I took a few pics on the tour. Let me know if you spot any ghosts in them!