Bullfights in Costa Rica are somewhat out of the ordinary. What's known as a "bullfight" here actually works backwards from most other countries.
The bull is immune, no harm may be done to it. No weapons of any type may be brought into the arena. The fighters are many, usually 20 to 30 are allowed in at a time. Most of them have no prior training or experience with bulls.
When the fight is started, the bull is released from the pen. From then on, any one of the bullfighters is fair game. The angry bull chases down anyone who might get in the way, and ocasionally stomps or throws a few of them into the air. It's like the roman colloseum, only with a bull instead of a lion.
The attraction of the whole event is not to see the bull get hurt, but to see the bullfighter get hurt. Which happens pretty often, by the way. And despite the hazards involved, people will line up for hours, voluntarily, to get their chance in the arena with the bull. There's never a bull that comes out of the pen and doesn't have at least 10 or 15 people to chase down.
The most popular bullfights are in December in Zapote, San Jose. They start on the 25th of december and go until the first week of january. Tickets can be purchased at the bull ring, and go from $15 to $50, depending on the date, time and location of seats.
Admission to the bullfighting ground is, of course, free. Find the line outside the ring, get in it, and wait for your turn. Enter at your own risk, obviously. Minors (under 18) may not enter as bullfighters. Proof of age may be required in order to enter.