Cambridge Dance Party from 7 to 11 p.m. June 30 at City Hall, 795 Massachusetts Ave., Central Square. Free.

The free annual Cambridge Dance Party that started with only 500 attendees in 1996 will likely have more than 30,000 this year, when it takes its place in front of City Hall on streets closed to traffic. A DJ will spin, and a colorful light show begins as dark falls. Information is here.

CONcentrate On The ARTistry II from 6 to 10 p.m. Saturday at The Center for Arts at the Armory, 191 Highland Ave., Somerville. Tickets are $15 in advance (with a $1.82 online service fee), or $18 at the door. An afterparty is $5 (with a $1.27 service fee when bought online).

The idea here is to showcase talent that goes largely unrecognized, and the hosts – the CONcept Artists troupe (above, in a Joseph Lee photo) – have found more than a dozen musical and dance performances to bring to the stage for this second year, including Miguel Almario, Rachelle Maguire, Isiah “Move Like Zay” Beasley, LadyIce, Jeryl Palana, Junior Cius, Emily Stomski, Steven Garcia, Smallie Michelle, Subject:Matter, Yiota “YoYio” Zeitinidis, Gil Vargas, Angie Wolfrum and Ashton “Stackz” Lites and Chad Shabazz. Information is here.

Sacred Spaces dance from 8 to 9 p.m. Saturday in The Pit, 1400 Chester Square in Harvard Square. Free.

This takes place in the middle of Harvard Square in a place that’s not sacred in the typical sense, though certainly is to generations who made it a home away from home, and sometimes a homeless away from home: The Pit. Kae Ishimoto and Wendy Jehlen will occupy it temporarily with a new duet that will become part of a larger work by Anikaya Dance Theater called “Conference of the Birds,” commissioned by the Boston Center for the Arts. Information is here.

Summer BCMFest from 10 a.m. to 9 p.m. Sunday on Palmer Street, Harvard Square, including  a paid brunch show, free outdoor festival and evening show for which tickets are $18.

This isn’t as big a deal as the winter version of BCMFest, which bring in more than 100 performers over the course of a weekend to celebrate Irish, Scottish, Cape Breton and other Celtic music. But there’s still two and a half hours of free entertainment starting at 2:30 p.m. out on the street with Keltic Kids, The Rockport Celtic Duo and Alba’s Edge. Before the free stuff comes a Live Music Brunch inside from 10 a.m. to 2 p.m. with the traditional Irish music trio Daymark; after the free stuff comes a ticketed evening performance inside again with Daymark and Scottish/Cape Breton-style fiddler Katie McNally (above). Information is here.

“In Triplicate” closing reception from 6 to 8 p.m. Sunday at The Nave Gallery Annex, 53 Chester St., Davis Square, Somerville. Free.

This closing June show celebrating the power of three – starting with turning the rooms in this house into three distinct art spaces – offers a last glimpse at the works (including Inguna Gremzde’s tiny oil-painted landscapes, called “Small World,” barely seen above) as well as performances by the Make Art and Cry Collaborative and Karen Krolak with Monkeyhouse. Information is here.