I would love to jump on a jet plane this January and travel to Argentina. I know a few folks that have done that for New Years eve, and might be going again. Flying down to South America over the new year would be a blast, then think of all the fun things you could do once you got there.
My parents went two years ago and stayed at a few hotels in Buenos Aires. They had their favorite breakfast spot and of course danced their way around the town.
A few of the things they did while on tours in Argentina were tango lessons, tai chi in the park, and visiting the cemeteries in the area.
But there is more to Argentina that just Buenos Aires. I think if I were going I would plan for a two week jaunt around the country from top to bottom. There are many different tours that last from a few days to a few weeks. They will set up all the hotels in Argentina for your trip so all you have to do is pack your suitcase. Remember the climate though, since they are south of the equator, the seasons are opposite!
It would be an adventure what ever season you decide to go in!