THEATER: “Doctor Horrible’s Sing-a-long Blog: A Musical by Joss Whedon” @ Caffe Lena, Saratoga Springs. 7pm. $10.
MUSIC: “Irish Christmas in America” @ the Iron Horse Music Hall, Northampton. Featuring an all-star gathering of musicians, including Oisin Mac Diarmada (of Teada ), Seamus Begley, Aaron Jones (Old Blind Dogs), Sean Gavin (Bua), Grainne Hambly, Sean Mc Elwain (Teada) and Brian Cunningham (Atlantic Steps). 7pm. $30.
PARTICIPATORY MUSIC: The Nellies’ Bluegrass Jam @ Jose Malone’s, Troy. It’s the final Americana-bluegrass jam of the year with your co-hosts Mike McMann and Peggy Lecuyer of the Nellies. Bring your instrument and sit in. Or just sit and listen. 7pm. FREE.