I don't know what to do at a hackathon

This year's Wikimania starts tomorrow! It's a huge conference for anything related to Wikipedia, Wiktionary and any of the other Wikimedia projects.

I'll be attending the hackathon tomorrow and on Thursday, but I don't really know what that entails. Will I be able to work on the Wiktionary translation editor? Perhaps I'll be inspired by what everyone else is doing, and want to help them out? I'm not really sure how to prepare, or whether preparing is even a good idea.

I do look forward to the hackathon, even though it scares me a little.