Spent Saturday at BCB4 - http://www.barcampboston.org/ twitter #bcb4
It was well worth my investment of time, and I regret not being able to attend Sunday as well. The un-conference concept worked well, the organizers did a great job, and several of the sessions I attended were really useful and interesting.
In particular: Raw Data: Facilitating Data Reuse on the Web, and How to Go from PHP to Django
There were other sessions I missed that I would have liked to attend but for the restriction on being in two places at once.
Here is a quick random snap of some of the crowd