Fenway News Online reports movie filming will be going on in and around Fenway Park starting this weekend, and that "they will be doing a lot of stunt and special effects work, including simulated gunfire." Also, "there will be some helicopters related to filming."

Boston Fire Department reports the cause of the carbon monoxide was "a small hole" in a boiler that let the gas escape into the hotel ventilation system. No injuries.

Local 718 tweeted around 10:15 a.m.

Fire crews still on scene at the former Charles Street jail an hour later, when Local 716 tweeted CO meters on multiple floors were showing levels of 20 parts per million (ppm), with peaks as high as 53 ppm. The lower levels are considered a potential problem for young children and people with serious breathing issues; the higher levels are considered "excessive" and anybody exposed to them should be checked by a doctor.

Among the evacuated guests, spotted by Phillip McCarthy:

[A] guy standing at the corner of Pinckney and Charles streets with two diaper-clad monkeys on his shoulders.

Channel 5 reports the monkeys are staying at the hotel while they film "The Zookeeper." No word if they're distraught over the death of their co-star, Tweet the giraffe.

On Friday, look for some unusual goings on at the southeast corner of Mass. Ave. and Beech Street near Porter Square, where some folks will convert a vehicle space into a play space. Angie explains on this Facebook page:

A creative exploration of how urban public space is allocated and used. In this space, you will find brightly decorated hula hoops. Please grab one and spin with us! Bonus: try some home-made soda. ... More than 70% of most cities' outdoor urban space is dedicated to private vehicles, with only a fraction of that land allocated for open spaces for people. We're taking a single parking space to see how easily that real estate can be transformed to benefit people. ...

There's at least one in Gloucester.