The #Wikimedia Localisation team will be going. I doubt it is wise for us to wear flowers in our hair as the song suggests.
Localisation and Internationalisation is very much part of any and all software development. For MediaWiki this is established principle; updates to the software go to translatewiki.net on a daily basis and the text of messages is often improved to allow for localisation.
Staying at the Wikimedia Office will allow us to improve our contacts and consequently improve our effectiveness. Yes, we will have "some" fun but without it it is just a job and we are passionate about our mission.
One thing that is REALLY exciting is that we will discuss how and when to bring the WebFonts extension into production. For me this is like a dream come true.