In an academic conference, where there are too many researchers and too little time, there are often 'poster presentations'. People conducting research will summarise their research on a poster and then stand next to it. Others walk around, looking at the posters, and stop to engage the researcher in questions and discussions about their research.

You can adapt this method as an unusual way to encourage free-flowing conversation. You can select a number of issues where you would like to encourage informal discussion. People can research the issue a little, prepare a poster, and one or two people can stand by it. They should be people with good communication skills. On the day participants then circulate freely and engage in discussions with people around that poster.

If you want you can combine this with some kind of summary at the end. Poster representatives can form a panel to discuss their experiences and summarise the debates they've had. Audience members can contribute too.

Pros:

It encourages everyone to participate as equals
 It allows a wide range of topics to be aired compared to other formats
Small conversations are often more rewarding than big group discussions
It's unusual and may catch attention compared to conventional discussion groups or workshops
In a long conference it introduces some variety

• It leaves participants completely free to engage or not engage, depending on the topic
• It is easy for people to avoid issues they'd rather not discuss
• Great way to meet people

Cons:

• It requires some dedicated individuals to prepare: to research the topic, make the poster, and have good communication skills (though different people can play different roles)
• It requires enough space to put up the posters, leaving enough room for people to mill around
• It requires large numbers of people attending the event if it's not to feel like a flop