Located about 15km outside of La Fortuna, the Butterfly Conservatory is an amazing project and well worth the drive from town.  The Butterfly Conservatory is a nature regeneration project.  The Conservatory sits on what was once a de-forested area slated for cattle ranching.  Reclaimed in 2003, the propietors have dedicated themselves to the restoration of the natural forest flora and fauna, with particular focus on butterflies, frogs and the plants of the Arenal Region.  For about $10, one is treated to a tour of the facilities, including  botanical gardens, 3 enclosed habitats, simulating the natural conditions in various parts of the Arenal area, a frog habitat, fish pond, as well as a laboratory used to hatch butterfly larvae.  The habitats are amazing, with hundreds of spectacular butterflies flying around.  The largely self-guided tour proceeds to a "Rainforest river walk" which was spectacular, and frankly much nicer than the other two rainforest hikes we had been on at the base of Arenal Mountain and Manuel Antonio.  One ends up at the Volcano View Gazebo, for a unique view of the Arenal Volcano viewed from the South West.  The workers at the conservatory were very friendly and knowledgeable, and best of all, you're off the main toursit route, which can be a mob scene during peak season.