see http://lanyrd.com/2013/unhostedpdx/
i myself would like to take the opportunity of having several gurus there to see if we can make some sort of browser plugin or Firefox OS patch that makes remotestorage.js store its data only once per device (or per device-user-profile) and not once per tab. that would mean you avoid the “initial sync” when opening an app, and would be a huge improvement.
apart from that, using WebRTC in unhosted web apps would also be an exciting topic to look at, i think.
but of course, it’s an unorganized event, so let’s see what the participants want to work on once we’re there!