For three weeks in January I studied Spanish at the University of Havana. Classes are in a group setting, and students are placed into different levels on the first day. The teachers were great and very patient, and the group classes were a fun way of meeting people and getting yourself accustomed to living in Havana.
To register for Spanish classes at the University, show up on the first Monday of the month. Classes begin at 8 AM, for 5 hours per day, Monday to Friday and cost 300 CUC for the month. You can attend for less than a month, but the prices doesn't drop by a proportionate amount.
At the end of my three weeks tho, I found there were too many different levels amongst the students for each person to improve as quickly as they could, more serious students might benefit more from private classes.
After my classes at the Uni, I took private lessons with a retired Spanish professor from the University, Aide for 5 CUC an hour. I think that I learnt more with just four hours of private instruction a week for a month, then with 15 hours a week at the Uni!
Below photos of our class, we were an interesting mosaic of Canadians, a few Europeans and one student from Japan.