Pop-up art show from 6 to 10 p.m. Friday at 1075 Cambridge St., Inman Square. There is a $5 suggested donation.

The space that once hosted a pop-up pickle shop (Grillo’s) and pop-up jeweler (Little Pancakes) now hosts a one-night-only pop-up art show with new paintings by Mary Galli (whose work is pictured above) and graffiti artist Not Art, with special guest Chris Murphy and DJ Trash Clambake, formerly known as Jugtown Radio. A donation of $5 or more gets free raffle tickets at the door. Information is here.

Bull McCabe’s fifth annual Roots to Reggae Outdoor Music Fest from 2 to 11 p.m. Saturday at Bull McCabe’s, 366 Somerville Ave., Union Square, Somerville. Tickets are $10.

This fifth annual outdoor family-friendly music festival has outdoor eating, drinking, games and dancing to the sounds of The Tim Gearan Band (folk rock), The Silks (blues rock), Dub Down Crew (roots reggae), Dub Apocalypse (reggae), Dave Wells (singer-songwriter) and the Ali McGuirk Band (R&B, soul, jazz and pop) – including possibly some of the best dub and island music you’ll find at a traditional Irish Pub that happens to serve everything from hummus to nachos and buffalo tempeh. There’s a free, 21-plus afterparty at the Thunder Road nightclub for ticket holders. Information is here.

Sixth Annual “Smoke This” Rib Fest from noon to 4 p.m. Sunday at 622 Cambridge St., East Cambridge. Tickets are $25.

The East Cambridge Business Association brings back its “Smoke This” Rib Fest, a culinary showdown pitting pit master against pit master for the title of the best ribs in town. Taste Tickets get you 10 rib samples from the restaurants of your choice, although each restaurant also sell ribs separately. Participants include Abigail’s, ArtBar, Atwood’s Tavern, Cambridge Brewing Co., Catalyst, Champions, Commonwealth, East Coast Grill, Hops N Scotch, Lone Star, Lord Hobo, Loyal Nine, Olé Mexican Grill, Portugalia, Puritan & Co., State Park and Trina’s Starlight Lounge. Joining in the competition are the Cambridge Police Department Pitmasters, Filarmonica Santo Antonio Cultural Center and Rindge Vocational Culinary Arts Students. There will be games for kids with The East End House and music by Vapors of Morphine, The Silks (it’s a busy weekend for this band), Monday Night Bluegrass and the Roy Sludge Trio. Information is here.

Haiti and Brazil Hit the ’Ville! from 1 to 7 p.m. Sunday at Union Square Plaza, 90 Union Square, Somerville. Free.

This event of song, dance and art celebrates two cultures in one event, since Haitians and Brazilians – which have much in common, including love of carnival and soccer – are both prominent parts of Somerville’s diverse population. Local Haitian restaurant Blessings, among others, will serve traditional foods such as Haitian Fritay and Brazilian Churrasco, and there will be dance demos, poetry, drumming and music. Information is here.

Harvest Festival from 2 to 4 p.m. Sunday at the Somerville Community Growing Center, 22 Vinal Ave., near Union Square, Somerville. Free, but donations are accepted.

Celebrate the harvests of the season with pumpkin decorating, games (including seed guessing), music and fall fun. There will be sugar pumpkins for sale as long as supplies last. Information is here.