Like cheese, classical music is best enjoyed when in string form. Snack on the sounds of cultured compositions with today's GrouponLive deal: for $11, you get one general-admission ticket to see the Celtic Christmas Extravaganza, presented by the Boston String Quartet at the Barre Opera House on Thursday, December 22, at 7 p.m. (up to a $22 value, including all ticketing fees). Doors open at 6 p.m.

The Boston String Quartet's talented team of bow-wielding virtuosos delights ears by offering programs that fuse classical repertoire with contemporary pieces. The Celtic Christmas Extravaganza regales listeners with a festive lineup of holiday tunes, including "Carol of the Bells," "Do You Hear What I Hear?" and "Silent Night." Singer Pan Morigan weaves her ethereal vocals through stringed melodies, with an octave-hopping range that caresses ears like a familiar fur hat. Originally opened in 1899, the Barre Opera House elegantly houses concerts in turn-of-the-century splendor. Recent renovations include soundproof windows and an advanced heating system, keeping patrons toasty during concerts and protecting the hall from rabble-rousing snowmen.