This document announces the first ever JRubyKaigi conference happening on August 28, 2010 as a sub-event of RubyKaigi 2010. It will include keynotes from Charles O. Nutter and other speakers such as Nick Sieger, Takeru Sasaki, Koichi Fujikawa, Yoko Harada, and Hiroshi Nakamura who are JRuby core developers and Japanese JRuby developers. Lightning talks are also being accepted.