Scituate
Sort of like "sit chew it," but not really.
Leicester
"Molester" without the first name of the slap-happy Stooge. Remember, the "r" is non-rhotic.
Billerica
Silent "e," and "rica" is pronounced like My Friend Flicka.
Gloucester
The people who make the Gorton's Of Gloucester commercials pronounce it wrong. It's actually sort of like "Gloss Stir"... if you pronounce that last R, that is.
Worcester
I was a security guard at the Worcester Centrum one year, and I saw Kenny Rogers botch this one. "Me and the boys travel across the land, but we always love it when we come back to War Chester." Someone up front shouted the proper word, causing Rogers to make a confused face and say, a bit more properly, something that sounds a bit like Rooster. The town is sometimes pronounced like the steak sauce, and vice-versa.
Somerville
The best way I can explain this without maxing out the syllable-syllable-syllable thing is to say that the Beach Boys or the Heat Miser should live here. Ironically, this is where Winter Hill is.
Leominster
Lemon-stir, quite possibly named so that people with a jar of water and some sugar would never forget how to make lemonade. Bree Sisson, the WBZ newsie from Jacksonville, always stumbles over this one. I forgive her.
Chicopee
Sort of like "chicory," but not really. This mostly just fools foreigners, but it fools them badly.
Sandwich
One thing that I discovered when I moved to Cape Cod is that about 20% of the people I know pronounce this as "Sammich." It goes up to 35% if the town name is dropped mid-sentence.
Tyngsborough
"Ting," not "Tying." Also, note the over-lettering of what should be "boro." Many towns, including Middleboro and Foxboro, refuse to use the ugh ending. No, none of these town names end in a way that rhymes with "cough."
Rehoboth
People who write dictionaries- who may just have one guy who specializes in the little ruh-hoe-buth parts of dictionaries- know how to tell you how to pronounce this. I can't do it, at least not in print.
Cataumet, Waqouit, Weqauquet, etc...
Cape Cod's town names are easy, but they make up for it by having impossible village names.
Woburn
The "o" is pronounced exactly like the "u" is pronounced in "tuba," because... well, f*ck you.
Haverhill
More "shave" than "have." A rare pronounced R sound in a Massachusetts town name.
Cotuit
"O" as "uh," then the last part of "Do it to it." Yes, the "o" is a "u" sound and the "u" is an "o" sound. We may one day be invaded by a foreign power, but they will not sneak up on us if they have to talk at all.
Fairhaven
You'd think that "fair" is in this word, but you'd be wrong. The "ir" was put in that word just to fool the British. The remainder of the prefix is pronounced like a longer way to run... provided that The Sound Of Music is set in Mission Hill.
Duxbury
Childe Stephen made a relatively quick leap from Dorchester to Quincy to Duxbury in the 1970s. Duxbury is about where, after Busing, the Boston accent runs into the more clipped Cape Cod accent. I spent 4th and 5th grade being removed from regular class for Speech Therapy, and all of it was me, over and over, having to say words like "farther" and "carnivore" as they exorcised my Southie accent like I was Regan MacNeil. As for pronouncing Duxbury, some people pronounce the end like Miss Sisson's first name, some say it sort of like "berry," and some say it sort of like the last part of Kitty Purry. The first part is like "Ducks," and not at all like Frank Dux from Bloodsport.
Tyringham
"Tier," not Tie."
Cochituate
Next....
Hyannis
More "Buy Ann this" than "Uranus."
Nahant
Just as confusing backwards as forwards.
Eastham
Looks easy enough. The end can be a deal-breaker. I threw this article up on the Eastham FB page, and there is some debate ongoing. 'Ham or 'Hum, choose your side wisely. It is tied very heavily into how one pronounces "Chatham." I'm an Upper Cape guy, this is Outer Cape stuff, and I can't be the one who makes the call.
Housatonic
Should be in Texas, and used as an adverb.
Wellesley
Also should be used as an adverb.
Mattapoisett
This isn't that hard to pronounce, but you have to stare at it for a second before you do so.
Quincy
Your favorite TV coroner pronounces his own name wrong, there's a Z in this.
Assinnippi
A little bit of Mississippi, in Norwell.
Assonet
Sounds like a crude name for pantyhose.
Cambridge
More "I came, I saw..." rather than Cam Neely's first name.
Padanaram
The nice part of Dartmouth, but it sounds like a level of Hell.
Truro
A rare Massachusetts word that pronounces both "r" sounds. It fools people who try to fake a Boston accent by dropping every "r." The actor who portrayed Cliff Clavin would have Jacksonian seizure if "Truro" came up mid-sentence on the teleprompter.
Amherst
No "H."
Acushnet
"A cushy net," minus the "y." The town seems to be named after a hammock.
Groton
Rhymes with "cotton," I think. I don't get there much.
Athol
