What types of sessions are appropriate?

The folks at unconference.net suggest the following possibilities:

The longer formal presentation

This is tricky, because it’s difficult to make a formal presentation interactive. But if you have a big, well-developed idea you can pull it off.

A short presentation to get things started

5-15 minutes of prepared material/comments by the session leader followed by an interactive discussion.

Group discussion

Someone identifies a topic they are interested in, others come to join the conversation and an interesting discussion happens

My big (or little) question

You have a question you want to know the answer to, and you think others in the group could help you answer it. This format could also just be the seed of a conversation.

Show and tell 

You have a cool project, a demo, or just something to show and let people play with that is the springboard for all the conversation in the session. Alternatively, you can invite others to bring their own items to show and tell (perhaps with a theme), and everyone takes a turn sharing.

Learn how to do X

If you’re inclined to teach, this can be simple and effective. Bring the equipment that you need, and have a plan that will let you teach five, ten, or 15 people how to do something all at the same time.