The temperature is starting to drop and the leaves are starting to lose their green color — clear signs that fall is beginning. Enjoy this first cool weekend of the year by catching an exhibition hockey game, conference openers for the soccer teams and a festival dedicated to that staple of many a local pantry, Fluff.

All that jazz: This Saturday, six blocks of Columbus Avenue between the Columbus lot and Mass. Ave. will be foot- traffic only — and a lot of those feet will be tapping, to the rhythm and swing of the Berklee BeanTown Jazz Festival, a daylong celebration of music and one of the city’s largest music festivals that starts at noon.

Return to Matthews: Hockey is back at Matthews Arena on Friday night, as the women’s squad faces off against the Ottawa Junior Senators in an exhibition matchup at 7 p.m.

Conference kickoffs: The men’s and women’s soccer teams begin their conference seasons this weekend with matches against Virginia Commonwealth University. The women, whose Veronica Napoli set the career goals and points records with two goals against URI last Friday night, play at Parsons Field at 6 p.m. Friday. The men’s home game at Parsons starts at 6 p.m. Saturday.

Fluff-y festivities: The locally revered Fluffernutter sandwich hails right from Somerville, Mass. And this weekend, the region celebrates the gooey white spread with its annual Marshmallow Fluff Festival in Union Square, complete with cooking contest, messy competitions, and performances by the Flufferettes, the premiere (and perhaps only) musical group dedicated to Fluff. The event will be held in Union Square on Saturday, Sept. 24 from 3 to 7 p.m.

Big Dog 5K: Northeastern’s annual 5K run along the Esplanade may be sold out with no space for new runners, but you can still head down to the Charles River Saturday morning to cheer on students and alumni! Registered runners can pick up their bib numbers early by stopping by the Alumni Relations office at 716 Columbus Avenue today.Race starts at Hatch Shell at 10 a.m. with registration starting at 8:30 a.m.

Tick-tock: The Boston art world is buzzing about “The Clock,” the MFA’s new 24-hour exhibition by artist Christian Marclay, who remixed thousands of video clips of clocks, watches and time-related dialogue timed precisely to match the clock. Admission to the MFA is free to Northeastern undergraduates (with student ID); entry into the 48-seat theater in the MFA’s new Linde Family Wing for Contemporary Art.