Hi,
if you arrive early in Buenos Aires (Sat. 22nd or so), you may want to join us in exploring the city. We, that is a travel group of (currently) four Wikimedians. If you are interested, please read the following page: http://wikimania2009.wikimedia.org/wiki/Travel_coordination#Sightseeing_in_B... You can add yourself as attendent on that page, too (don't worry, it's not bindingly).
Of course, if you aren't interested you may want to check out the travel coordination page anyway, as there are also other exciting travel proposals.
Yours,
Church of emacs