If you haven’t been to a sing-along Messiah yet, it’s the time of year to warm up your vocal chords and find one. These performances are seasonal treats — unless you’re a musician, in which case they could be an occupational hazard.

But for the rest of us, there aren’t many opportunities for genuine amateurs to belt out music, in a theatre, surrounded by hundreds of people doing the same thing, backed by a professional orchestra and possibly a choir. Since Handel's Messiah debut in 1742, it's proven a massive hit with crowds. At some point, those crowds wanted to sing along, and a tradition was born.

"It’s a unique, musically edifying — most of the time — occasion," says Gregory Wait, music director at Schola Cantorum Silicon Valley, which hosts its 51st annual sing-along Messiah this year. That would make it the oldest sing-along Messiah in the Bay Area.

"Everybody gets to kind of sing everything," Wait says. "I jokingly ask attendees to attempt to sing them in the octave written, but that doesn’t always happen."