There's lots of interesting stuff in this thread - thanks for your views everybody!

I find that most people are saying what I feel. In a larger singaround (like when it takes about three hours for everyone to sing once) there has to be somebody in charge and it's only fair to give everybody an equal chance to sing, although favouring the people who've been there all the time over someone who's just popped in. Going round the room means that people should know when it's their turn and be ready.

A smaller impromtu gathering can look after itself (but it's a good idea to note that if someone isn't getting a go to invite them to sing).

The rest of this works by concencus. Accompaniment (and tunes) are allowable if the majority of people in the room want them.

At the risk of a little thread creep I would ask singaround participants to be ready. The idea of going round the room in order means that you can work out when your turn is and pick your time to go to the bar and/or the toilet. You should have more than one song in mind, in case the mood needs changing. Your instrument (if any) should be ready to play, and not in its case on the other side of the room in the wrong tuning. If the person whose turn it is announces what key the song or tune is in, then other people can join in the accompaniment (and not take over!)

I have lots of fun in singarounds and general sessions both locally and at festivals and I find that they nearly always work very well - partly because people know each other and also because there's plenty of respect around.

Les