St. Patrick´s Day is on March 17th. You can watch a video about St. Patrick´s Day here: https://www.youtube.com/watch?v=CXmxooGQ_Dg
Everything is green on this day – beer:
even a river in Chicago!
People celebrate this day wearing green as well:
The traditional meal is Irish lamb stew – easy peasy (= not difficult) to prepare: http://www.goodtoknow.co.uk/recipes/312502/irish-lamb-stew
Some people dance jig: https://www.youtube.com/watch?v=hDIZ6lsCKtg
If you catch a leprechaun (a tiny little man) on this day, he has to give you his pot of gold usually hidden at the end of the rainbow.
And finally some numbers: http://cdn.history.com/sites/2/2014/01/st-patricks-day-infographic-final.jpg