Probably the most important is lent and Easter. The first day of lent is Ash Wednesday, and lent culminates in Holy Week which includes Palm Sunday, Holy Thursday, Good Friday and Easter Sunday. Then there is advent and Christmas ofcourse. I am Catholic so we have days for the saints but they are not hugely important. We also acknowledge the assention, the assumption, all saints say, trinity sunday and sometimes the immaculate conception of Mary and the epiphany.
Christmas, which is Jesus' birth, Easter, which is when Jesus rose from the dead, Good Friday which is when Jesus died on the cross, and some observe Lent and Holy Week, which I guess I kinda do Holy Week but not hardcore lol
Christmas parade, Christmas give away at churches, where they give gifts and everyone has dinner
christimis and new year festivals