Yule Open Ritual from 5 to 9 p.m. Friday at The Democracy Center, 45 Mount Auburn St., Harvard Square. There is a suggested donation of $5 to $15.

Pagans and witches in the Cornucopia Collective offer a serious celebration of the turning of the seasons, with potluck and gift exchange (following a Hobbit tradition invented by J.R.R. Tolkien, participants are asked to give “mathoms” – items they no longer need but are unwilling to throw away) following a closed-door ritual starting promptly at 6 p.m. Information is here.

Festivus (for the Rest of Us) party from 9 p.m. Friday to 1 a.m. Saturday at the American Legion Marsh Post, 5 Greenough Blvd., West Cambridge. Tickets are $15 in advance ($16.52 with the online service fee) or $20 at the door, when it’s cash only.

Bass music from Los Angeles’ Da Moth (with support from DJs Tigress and Kibble) is the backdrop for a 21-plus cash bar party that includes visual projection, live art, face painting and chair massage. Look for the traditional celebratory dance around an unadorned aluminum pole, an Airing of Grievances when you can tell others how they disappointed you in the past year and a “Feats of Strength” dance-off challenge. The party is put on by the Camp Love and Lions Den communities to fundraise for travel to the summertime Firefly arts festival in Vermont. Information is here.

“Christmas in Medieval England” concert at 8 p.m. Friday and Saturday at First Church in Cambridge, 11 Garden St., Harvard Square. Tickets are $45 to $65 Friday; free to $65 Saturday.

One of three Blue Heron vocal ensemble performances of Advent and Christmas music from 15th century England has already sold out; of the two that remain, the Saturday event reduces prices to free for those 18 and under; $10 for students and the low-income; $27 for seniors; and $32 for general admission. Blue Heron delivers transporting motets, English carols and Sarum plainchant and there’s a preconcert talk by Harvard’s Daniel Donoghue in the 45 minutes before each concert. Information is here.

John Davis & the Cicadas, Rob Noyes and Evil English from 7 to 10 p.m. Saturday at Lilypad, 1353 Cambridge St., Inman Square. Admission is $10 at the door.

If you haven’t experienced John Davis since the days of Folk Implosion – or even if you have – you’ll be happy to hear “El Pulpo,” the October art-pop album that brings a savage bite and catchy licks to a political theme (in fact, specifically to agribusiness – Davis is a union activist in addition to an elementary school educator). The songs are reminiscent of Folk Implosion’s “One Part Lullaby” and “Kids” soundtrack filtered through the multilayered rhythms of Can. Local Rob Noyes and Evil English, out of Davis’ hometown of Durham, N.C., do opening sets. Information is here.

Moon Wok Jewish Christmas Event at 5 to 10 p.m. Sunday at Mamaleh’s Delicatessen, 1 Kendall Square, Kendall Square.

Reservations are recommended for this second annual Jewish Christmas Celebration (there’s another one Monday at the same hours) at this hip Jewish joint in Kendall Square, with “Jasian specials” such as Baked Brisket Bao, Whitefish Rangoons and Kung Pao Pastrami. After Monday, these dishes disappear for another year. Information is here.