Arrgh! It be celebrated every year on September 19. Here is a website to find more nonsense about the day. There is even a facebook group dedicated to it.
This year, a group, Pirates for Parkinsons, is using the day to march for Parkinsons Disease. To date there are 39 Pirates for Parkinson's walks or events, mostly in the UK, but others include: Amsterdam, The Netherlands; Dayton, Ohio; French Pyrenees, France; Ghana; Glasgow, UK; Hong Kong; Johannesburg, SA; Ketchikan, Alaska; Luxembourg; Plano, USA; Stockholm, Sweden; Sydney, Australia; Tokyo, Japan; Wellington, NZ; West Bank, Middle East. Glad to see that Plano is included. More info is here. Avast, mateys, have fun for a good cause. Let me know if you see any blonde pirates - They are the ones with patches over both eyes.