Dyngus Day

Okay, this is a new one to me. I've never heard of it before. Just found out a cousin from the Pittsburgh area, is traveling to Buffalo, NY to celebrate this day which falls on Easter Monday. I googled Dyngus Day and it indicates celebrations also take place in Wyandotte and Hamtramck.

Is there anyone on the forum who celebrates this day? If so, what typically takes place and where do you celebrate? Do you go to a rented hall, use church facilities? I'm just curious since I've never heard of it before. Having been raised all around the Polish community and having several in-laws who are Polish, this day of celebration has never been mentioned to me.