The Sacraments are outward signs instituted by Christ that impart divine grace to those disposed to receive them. The seven Sacraments were instituted by Jesus and His Apostles and form an integral part of what it means to be a Christian. All celebrations of the Sacraments are done through the liturgical life of the Church.
The seven sacraments which are grouped into three types:
Sacraments of Christian initiation
Baptism
Confirmation
Eucharist
Sacraments of Healing
Penance / Reconciliation
Anointing of the Sick
Sacraments at the service of communion and the mission of the faithful
Holy Orders
Matrimony
This grouping, while not the only one possible, does allow us to see that the sacraments form an organic whole in which each particular sacrament has its own vital place. In this organic whole, the Eucharist occupies a unique place as the "Sacrament of sacraments": "all the other sacraments are ordered to it as to their end."
[from the Catechism of the Catholic Church, paragraphs 1210-11; quote is St. Thomas Aquinas, Summa Theologiea III, 65, 3]