BarCamp is a “participatory unconference”, so you, the attendees are going to be making the event as great as it can be. The idea is that everyone who comes takes part in some way: that might be running a session (which is not as scary as you might think), taking photos, blogging, tweeting etc.
You can run a session on anything you want. Really: anything. Your session needn’t be technical or formal, and can be in any style you are comfortable with. We’ve had sessions on all sorts of topics in the past such as mixing mojitos, photography, lifehacking, and making sushi (and plenty of other stuff), right through to advanced discussions on programming, hardware hacking, and web design. Take your pick!
A good tip is to head to sessions that you know less about, that way you will learn more. If you don’t see a session on something you are interested in, you might want to run a discussion or sharing session where you can all just talk about something - whether that’s kittens, Python or juggling.
Informal presentations or discussions are allowed too: you don’t have to stand up and give a presentation with slides, you can simply sit round and have a discussion. Just introduce the session by saying who you are and why you are interested in the topic and ask people in the session to share their ideas and experiences with that topic.