Ephemerisle (http://ephemerisle.org/wiki/Ephemerisle) is a floating festival of art, anarchy and radical self-reliance in the Sacramento River Delta, organized by a loose group of amateur maritime hackers. Many bitcoin enthusiasts attend each year to enjoy living in a truly free community, however briefly, and learn from others. Originally sponsored by The SeaSteading Insitute (http://seasteading.org), the event is no longer sponsored by anyone except the people who attend.
It isn't exactly Burning Man on the Water (as some have described it), but resembles the early days of Burning Man before it grew into a monster. Unlike Burning Man (TM), Ephemerisle is a voluntarist-organized, non-ticketed, non-permitted open party and free enterprise zone where capitalism and the start-up mentality are enthusiastically encouraged. No government gives us permission because we don't bother to ask. The coast guard always checks up on us, but that's their job and we follow all their regulations so they don't hassle us. More often, they are happy to help us as well. We like that.
The cost is up to you. You just have to find a way to transport yourself and your gear to any one of several island flotillas of houseboats, sailboats, kayaks, Jet-skis and assorted hand-made Build Your Own Land (BYOL) floating platforms anchored off of Mandeville Tip County Park. (https://maps.google.com/maps/ms?msid=207854270338809155245.0004864803082020221ed&msa=0)
How do you get there? Check the wiki to find boat captains who may have room for another body on their vessel (and help pay your part of the rent). Or you can volunteer to crew any one of a handful of sailboats that will make their way from the Bay Area to the delta that week. Or find your way to either the Paradise Point Marina the first day of the event and help build the thing, or H&H Marina at 15135 W Eight Mile Rd, Stockton, CA 95219 (which is the closest point to the location). Parking is $2/day.
If you have a speedboat, you can help shuttle guests back and forth from H&H to the event and meet tons of new best friends. If anyone wishes to share the costs, we can rent a Patio Boat that is slower than a speedboat, but capable of carrying up to 8 passengers (speedboats can't accommodate more than 6, and they have to sit on their baggage). This provides a valuable service, costs only a couple hundred bucks and you can also sleep on the patio boat if you have a hammock and sleeping bag.
Come for the whole event, or get there whenever you can. The population swells from Friday to Sunday, but many people (“Day Trippers”) come only on Saturday just to get a taste of it.
Be aware that you are going to be living on the water, in dangerous conditions, and there is no insurance. People help each other and take care of things because it's the right way to build a community, so be prepared to give as much as you receive.
I first learned about bitcoin at Ephemerisle 2011, and I know several boat captains who would be happy to take your bitcoins over Federal Reserve Notes or precious metals.