A tennis course tailored to your specific requirements. The company can also combine it with Tango lessons and Spanish teaching and conversation. I'd recommend this because of the high quality of the tennis facilities and coaching (my coach had worked with players on the ATP circuit and top five juniors from across South America) and because of the excellent personal service received (recommendations on food, cultural and leisure throughout BA, an individual tour of the city from a lecturer in the History of architecture from the University in BA, visits to nearby haciendas etc) the holiday allowed me to combine intensive tennis coaching with a relaxing visit to BA.
The Australian Open tennis tournament, during the last 2 weeks on January is a must. Tickets are reasonably easy to get hold off if you try the day they come out (Early October), and they are cheap, $70ish for a seat in the Rod Laver Arena.