What are peoples 'special' interests?

Im curious to know what other peoples interests/hobbys are.  Recently I have been studying/growing mushrooms/mycology.  

Before that, it was keeping/breeding tarantulas and invertebrates.  I also have a vast knowledge of insectivorous plants.  As a kid, i practically knew every football player who played in each team.  Was obcessed.  Not so much now.  

So, what is everyone else like to study or spend time one?