Festival2011/Badges: What's an OBI and How Do I Use It?
Why people should attend your incredibly cool session.
What you need from participants for the session.
How people can get involved with your project after the festival.
Session hash tags specifically for notes on your session, and hash tags specific to your project for promotion.
Don't just do it, let people know what you did! Links to all assets generated during your session, photos, video's, blog posts, sketches, all the artifacts from your session.
EtherPad for the session to take notes and collaborate