Fluff Fest 2026

What the Fluff? A Tribute to Union Square Innovation is a madcap festival honoring the invention of Marshmallow Fluff, returning for its 21st year with live music, fluffalicious feasts, sticky games, and zany happenings. The festival runs from 1–5pm in Union Square, Somerville. MassBike will be offering free bike valet for all festival attendees.