The liturgical life of the Catholic Church revolves around the Eucharistic sacrifice and the Sacraments. As you know, the seven Sacraments are: Baptism, Confirmation, Eucharist, Penance, Anointing of the Sick, Matrimony, and Holy Orders.
The purpose of the Sacraments is to make people holy, to build up the body of Christ, and finally, to give worship to God; but being signs, they also have a teaching function. They not only presuppose faith, but by words and object, they also nourish, strengthen, and express it; that is why they are called “sacraments of faith.” The Sacraments impart grace. In addition, the very act of celebrating them disposes the faithful to most effectively receive this grace in a fruitful manner, to worship God rightly, and to practice charity.
Mariage and Confirmation have their own sections with resources on this site; below are just a few resources for each of the other Sacraments.
When the Sacrament of Baptism is administered, the spiritual vacuum which we call original sin disappears as God becomes present in the soul, and the soul is caught up into that sharing of God's own life which we call sanctifying grace. The Sacrament of Baptism not only gives us sanctifying grace: it also makes us adopted children of God and heirs of heaven.
Since the Holy Eucharist is a spiritual food, it does for the soul what physical food does for the body. When we eat physical food, it becomes united to us—it is changed into our own substance and becomes a part of us. In Holy Communion something analogous happens to us spiritually, but with a great difference: in this case it is the individual who is united to the Food, not the Food to the individual. The lesser is united to the Greater. We become one with Christ.
As with all the sacraments, the Anointing of the Sick confers sanctifying grace. It was instituted by Christ to give spiritual aid and comfort and perfect spiritual health, including, if need be, the remission of sins, and also, conditionally, to restore bodily health, to Christians who are seriously ill.
The sacrament of Holy Orders creates a priest. In this sacrament, Christ has provided us with an essential link to himself. Above all else, Holy Orders makes possible the extraordinary gift of the Sacrifice of the Mass—a gift from Christ himself.
The peace of mind and soul which this sacrament imparts to us is one for which there is no substitute. It is a peace that flows from a certainty, rather than from an unsure hope, that our sins have been forgiven and that we are right with God.
The sacrament of Penance is also known as Reconciliation and Confession, but "penance" best describes the essential interior disposition required for this sacrament. The sacramental grace of Penance fortifies us against a relapse into sin. It is a spiritual medicine which strengthens as well as heals. A person intent upon leading a holy life will make it a practice to receive the sacrament of Reconciliation often.