What the Fluff? A Tribute to Union Square Innovation, a far-out festival honoring the invention of Marshmallow Fluff, returns to Union Square in Somerville.
Come play, delight in your food, and raise a glass to Union Square as What the Fluff? turns 21! This year’s theme – Legally Fluff: A Toast to Union Square – celebrates 21 years of fluff-filled fun for all ages.
What the Fluff? A Tribute to Union Square Innovation is presented by Union Square Main Streets and the Somerville Arts & Culture Division.
SIGN UP TO VOLUNTEERDays
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Severe weather and other emergencies can happen. Fluff Festival attendees can sign up for day-of emergency text alerts for this year’s event: text FLUFF26 to 888777.
Note: Festival attendees, as well as vendors and community groups, may not engage in promotion of religious groups, political statements, campaigning, petitioning, or signature gathering.

Try your hand at old-school, boardwalk-style games including Fluff Bowling, Fluff Ring Toss, and more at the Midway Games (free to play, free to win prizes!)
Innovation Alley presented by Somernova - where curiosity gets a little sticky, robots make s'mores, and innovation shows up in unexpected ways. Come for a s'more made by a robot, watch a live artist create, adopt a new marshmallow friend, and so much more!
Experience the thrill of this exciting sport with guidance from Somerville’s very own pros.
Get up close with some of the most exciting vehicles around town!
Flex your artistic skills and make some Fluff inspired creations with your local librarians.
Bring your two wheels without worrying about locking up with TWO FREE bike valets provided by Mass Bike.
Strike a pose with art installations by local artists including Nathaniel Devarie and Confetti Friends. Who knows what else you’ll discover at this one-of-a-kind celebration!
Union Square is short on parking. Best ways to get to the Fest are to walk, bike (free bike valet!), boogie, or take public transportation. If you must drive, we recommend that you park on the outskirts of Union Square. But really, we don’t recommend you drive, if at all possible.
Start from our Eastern Entrance in the Union Square Plaza (Union Square Station, Lechmere, Inman, Central, East Somerville)
Start from our Western Entrance near Market Basket (Porter and Davis)
Bring your two wheels without worrying about locking up with TWO FREE bike valets once again provided by our sweet friends at MassBike at each end of Somerville Ave!
We’re just a 25 minute walk from Lechmere, East Somerville, Porter, Harvard, Central or Sullivan Square.
Hop on the MBTA Green Line and ride directly to Union Square Station. From there, it’s just a short walk to the festival, starting in the Union Square Plaza!
Limited edition 2026 Fluff merchandise, including t-shirts, stickers, and koozies celebrating 21 years of sticky, sweet Somerville will be available at the Festival in the merch tent on Somerville Ave by the Parenting Journey building. Other fun Fluff stuff (totes, koozies, hats, sweatshirts & more!) will also be available!
GET YOUR FLUFF STUFFMention us or tag us @flufffestival on your instagram posts so we can see how you Fluff.
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