Apparently the building is being renovated by Harvard (their landlord) and so they have to close. Last day is December 17th (or 18th, not sure). Their sign says they hope to reopen in 6 months, but it didn't sound like a sure thing. Not that it's really ice cream weather now that the temperature is approaching absolute zero (yikes!) but their espresso drinks have lately been my favorites in the square; I really hope they do come back.
(To forestall any panic: this ONLY affects the Harvard Square location, not any of the other Toscys.)