The YUI blog has the following invitation:
Beer. Food. Music. Guitar Hero on the projectors. Some other goodies and a few announcements we think you’ll like. (No, not Beck.)
At 6:30 there will be a brief presentation by the YUI team. After that we’ll have “built-with-YUI mini-demos”, where some of you can take the stage for 5 minutes to show off how you’ve been using the YUI Library. There’s only time for a handful of these quick talks before resuming the music and party around 7:15, so leave a note in the comments or send me an email directly (natek at yahoo-inc dot com) to get your proposal in.