an event at which anyone is allowed to tell jokes, read poetry, sing, etc. on stage

There's live music with an open mic and a free pint for all performers. 有现场音乐和自愿即兴表演，为所有表演者免费提供啤酒。

It's a bit like open mic night at your local comedy club. 这有点像当地喜剧俱乐部的开放麦克风之夜。