An unconference is like a conference, in that it’s a gathering of people interested in a particular topic, who come together to share and learn. An unconference is unlike a conference, in that it doesn’t have a preset schedule of talks that you sit through: instead, the agenda is built on the day by the people who attend. Anyone can run a session, whether it’s to share something they’ve done, ask for help with something they’re trying to do, or just to kick some ideas around. The EYC unconference site has a list of topics people are interested in talking about on the day.
There are still places available - it'd be great to see you there, whether you're learning or sharing (or both).