LinkedIn, Joyent and Sun Microsystems is sponsoring a JRuby hackfest in conjunction with RailsConf. It will happen next Thursday from 6:30 PM in Portland, there will be some food and beer and so on. Oh, Charles, Nick, Tom and me will be there - bring your laptops and any and all questions/patches/bugs/ideas with regards to JRuby.
Read more in Charles blog, here: http://headius.blogspot.com/2008/05/jruby-pre-railsconf-hackfest-on.html
Remember to RSVP to Charles if you're coming. Space is limited so RSVP as soon as possible.