Aggregation No. 1Off-Mic at Gallery 263 from 8 to 10 p.m. Friday at Gallery 263, 263 Pearl St., Cambridgeport. There is a suggested donation of $10 at the door.

This neighborhood art gallery is so intimate that amplification is often totally unnecessary – and without a microphone, a barrier between performer and audience is knocked down, helping to give audience members a behind-the-scenes look at the creative process of performing. This month’s showcase of comedians, musicians and poets offers Zach Armentrout; Tawanda Gona; Emily Ruskowski; Mike Lemme; and Chris Post. Information is here.



Aggregation No. 2Porchfest, from noon to 6 p.m. Saturday throughout Somerville. Free.

Somerville’s “decentralized music festival” returns for its sixth year, presenting musicians on an underused public venue: the porch. Organizers at the Somerville Arts Council say acts range from Bollywood funk, cosmic Americana, killer blues and Moroccan to Balkan, gospel, American space rock and clawhammer banjo. This year there will also be a killer comedy porch at 5 Highland Road, near Davis Square, with shows at 1 and 4 p.m. (The second show is headlined by Dan Boulger, who just released the album “Not Ready for This.”) School of Honk plays from 4 to 6 p.m. in front of Winter Hill Bank at Summer Street and Cutter Avenue in Davis Square. And the Boston Hassle hijacks the event for a family- and dog-friendly loft party with nearly two dozen bands from noon to midnight at Pearl Street Studios, 226 Pearl St., in the Winter Hill neighborhood.

There are three time slots headed east to west, with noon to 2 p.m. porch performances in the eastern third of the city; 2 to 4 p.m. performances in the central part; and 4 to 6 p.m. performances happening west of Somerville’s Willow Street. There’s a complete map, performance time, date and style description, along with searchable band profiles (and even sample songs) here.



Aggregation No. 3“With A New Song’s Measure” staged reading from 8 to 11 p.m. Saturday at Unity Somerville, 6 William St., just off College Avenue near Davis Square, Somerville. Free, with donations accepted at the door; register here.

King Arthur clashes with the Roman Empire, putting Camelot at stake, in this play by debuting playwright Chris Chiampa. Directed by Liz Salazar with a full cast, this staged reading provides not just entertainment but a chance to see a play take shape – and to provide feedback to the playwright, director and cast afterward. Information is here.



Aggregation No. 4Second Annual Central Square Steam Family Disco from noon to 3 p.m. Sunday at The Middle East Downstairs, 480 Massachusetts Ave., Central Square. Free, but register and consider a donation here.

This free family event (geared toward kids ages 4 to 13, though younger siblings are welcome with supervision) aims to get everyone dancing to the spinning of two local youth DJs and to take a break with some science, technology, engineering, art and math concepts – it’s put on by the Central Square Business Association, Together Festival, the City of Cambridge’s El Steam Network and The Middle East. Adults must be accompanied by a child to be admitted, in a one-parent, two-kid ratio, and parents must stay downstairs during the event. Food and drink will be available for sale. Information is here.



Aggregation No. 5Waltz Day, with a dance lesson at 7 p.m. and dancing from 7:30 to 9:45 p.m. at The Democracy Center, 45 Mount Auburn St., Harvard Square. Admission is $10, or $7 for students.

The Miranda’s Hearth group offers this monthly inclusive dance with live music, this time from Light Reaction, made up pf Kathleen and Jim Fownes. Photographs will be taken during the lesson and until the break at 9:15 p.m. to be posted on Facebook. (The second half of the dance is photo free.) Information is here.