Did you know that Fluff was invented in Somerville’s Union Square 101 years ago? On Saturday, September 22nd, from 3:00pm to 7:00pm, come find out what all the Fluff is about at the 13th annual What the Fluff festival. It’s a fun-filled afternoon packed with music, games, and activities for all ages, and plenty of marshmallowy goodness, from treats to a cooking contest. This year’s theme is “Fluff the 13th,” meaning there will be black cats, magic, and mayhem at this celebration of Somerville’s innovative spirit. No tickets are required, but make sure you plan ahead for traffic—fluff is popular stuff, and the What the Fluff festival typically attracts over 20,000 participants. More info here.