I know they’re not strictly Protestant, but an unprogrammed Quaker meeting is unlike any other Christian worship service I’ve seen.
For those of you who have never been, here’s what it’s like:
The intent is to avoid as best they can any set ceremony so that they’re as free as possible to be led by the Spirit.
The seating arrangement varies, but in most meeting houses, the chairs are either arranged in a circle or with one bank of seats facing another.
Everyone goes into the meeting hall and sits down. Things begin with “waiting worship”: everyone sits silently and meditates or prays. If anyone feels “moved by the Spirit” to say or do something, they stand up and do it - maybe they say a few words, maybe they read a Bible passage, maybe they sing a hymn… there are no real limits. When they’re done, they sit down silently again. If someone else feels moved to speak, they do so.
The idea is to come to the meeting not planning to either speak or stay silent. Sometimes, a meeting will be fairly active; other times, nobody will speak at all.
At the end of the meeting, two of the elders shake hands, signalling to everyone else to shake hands with those around them as well. Usually after that, there’s coffee.