Among the many activities, apart from the lovely white sand and the Olympic-size swimming pool, are kayaking, snorkeling, scuba diving, water skiing, and riding wave runners. And for the more romantically inclined there is a wonderful sunset cruise.
The official currency of Costa Rica is the colon (CRC). Credit cards are accepted in many places, but traveler's checks in U.S. currency are even more widely accepted and are usually a good choice.