Maundy Thursday, Good Friday, and Easter Sunday are observed by Christians as the days that Jesus ate his last meal, was crucified, and rose from the dead. Many people honor the days differently, but there are a few traditions that most families keep.
Palm Sunday marks the first day of Holy Week. It's followed by Holy Thursday, Good Friday, Holy Saturday, and Easter Sunday. These days in the Christian faith hold much of what their religion teaches. Christians believe that Jesus died for their sins. Jesus was welcomed in to Jerusalem on Palm Sunday. He enjoyed the "Last Supper" and was betrayed by Judas on Holy Thursday (or Maundy Thursday). Jesus was arrested, tried, crucified, died, and was buried on Good Friday. Holy Saturday marks the day that Jesus rested in the tomb before resurrecting on Easter Sunday.
Good Friday is the one day that Christians mourn. Many people choose not to do any "fun" activities in the afternoon hours in remembrance of Jesus' crucifixion. Many people attend church services on this day (and every day of Holy Week).
Easter Sunday is almost always celebrated with family members. People tend to have big dinners and enjoy their lives as Jesus would have wanted. Next to Christmas, this is a very "popular" day to go to church.