In Poland, such a phenomenon as Long Weekend usually occurs several times a year (the Easter weekend, Christmas weekend etc.). However, the best known long weekend is at the beginning of May, when there are holidays of Labour Day on May 1 and 3rd May Constitution Day. The 3rd May Constitution (1791) is generally regarded as Europe's first and the world's second modern codified national constitution (as you probably know, world's first constitution was ratified in USA in 1788).
There are few patriotic holidays in Poland, but only May is a perfect time to celebrate it outdoors. Picnicks, barbecues, hitchhiking trips and many more ways to spend these days off.
I browsed through Etsy categories looking for items related with Poland. I just love this T-shirt saying "Hug me, I'm Polish"!
Ang here are earrings with polish words "TAK" and "NIE" which means "YES" and "NO". Adorable gift for anyone who loves Poland. Also check this polish stamps collection - small lecture on history of Poland.
Have a nice Long Weekend!