I like the "unconference" format. It's similar to the things I like about BiCamp and about good small con, in that there is no divide between "presenters" and "attendees". If you want to present something, just edit the wiki and add yourelf to the schedule. If you have a question, ask. If you want to talk to someone, stop them in the hallway and ask them.
My only expenses were airfare (and I already had some Southwest credit to burn up), and evening dining. And I ate in the evening just to fit in, the food at Google was plentiful.