People who like free software, and people they like, should attend. You might talk about free software, or you might not. A special FOSSy friend of ours from The Frozen North of Canada is in town for the week and might make an appearance.
Ben & Nick's has been the venue of choice for previous East Beowulf clusters. They're about half a block south from Rockridge BART, giving little excuse for those from westbay to skip out ;)