Green is associated with Saint Patrick's Day because it is the color of spring, Ireland, and the shamrock. School children have started a little tradition of their own -- they pinch classmates who don't wear green on this holiday.

    Irish lore of the day  
Leprechauns are also associated with this holiday. According to the legend, the Leprechaun is an Irish fairy. It is told that Leprechauns are unsociable, unfriendly, live alone. Also, they make shoes and possess a hidden pot of gold. The legend says if the Leprechaun is caught by a treasure hunter then he must tell where is treasure is, unless the Leprechaun can trick the hunter 
and vanish.