I've spent much of my life trying to get audiences to sing when they only came to listen. I thought it might be an idea to post this problem for discussion.
The main situations I confront are church services and kids' groups. Younger kids are no problem, but Catholics and teenagers are possibly the most reluctant singers on earth.
I find myself knocking heads with our choir director, who seems to think it's the role of the choir to perform, rather than to encourage the congregation to sing. I think his main problem is that he just doesn't belive the congregation CAN sing, and he doesn't know how wonderful congregational singing can be. I try to show him it can be done by weaseling in a chance for the congregation to sing when the choir director doesn't have a chance to put a damper on it.
Last week, I had to do a "commercial" at mass for the parish Oktoberfest, which happens this weekend. I closed my minute by having the choir and the congregation sing "Beer Barrel Polka." The people loved it, and they sang and clapped along. I imagine there will be discussion for weeks about whether my choice of that song was appropriate, but it worked (and it was used as part of an announcement of a social gathering, not part of the religious service - I do have SOME taste).
Anyhow, here are a couple of pointers I'd make, and I wonder what tips other people might be able to add:

-When you want a group to sing, move back from the microphone so you don't overpower them. People seem to sing along more easily wih an UNamplified leader
-Use humor to loosen people up and encourage them, but make sure the humor does not demean or belittle the audience in any way. Many people are shy about singing - they don't lose their shyness when they are belittled.
-Keep songs simple and upbeat. Consider having the group sing a simple chorus, while the leader or choir sings the verses.

Any other ideas?
-Joe Offer-