Altar Servers - "Altar servers perform most of the functions of the former ‘minor order’ of ordained clerics known as acolytes from the Greek word akolouthos or 'attendant'. The primary role of the altar server is to assist the priest in the celebration of the liturgy during Mass."
Communion Ministers - assist the Priest in the distribution of Holy Communion.
Lectors - assist at Mass in the proclamation of the Scripture texts.
Ushers - "We are the first persons that people meet when they come to church. We are the doorkeepers in the house of the Lord. The purpose of this ministry is to provide the logistical services that allow the Masses to run smoothly and attend to the special details that are part of large gatherings."