Grace

“By mortal sin a man forfeits his last end to eternity, and therefore eternal punishment is his due. No man can be freed by sin except by grace, and yet the sinner is to be blamed if he is not converted. Man needs grace to persevere in good, but no one can merit divine assistance.”

In Christian theology, grace is the unmerited favor of God bestowed on sinners. These blessings usually come in the form of "not going to hell" and "being a good Christian". Although almost all Christians agree that God's grace is necessary for salvation and sanctification, they tend to disagree on the means by which God bestows it. These arguments can get heated. In fact, the Protestant Reformation was largely a reaction to Catholic teaching on the means and nature of grace. Continuing the trends of the last two millennia, nobody understands what exactly grace actually is. We do know that these "unmerited" magical powers take a hell of a lot of work to get. Funny, that.

Means of grace
Different denominations and sects of Christianity believe in lots of things you have to do to obtain the "free," "unmerited" gift of grace. Grace seems like a great deal! (Almost as great as the $1,250,000 some Nigerian prince offered me later if I front him $15,000 by Western Union tomorrow. Nifty!)

Grace is also a category of prayer spoken before a meal which imbues food with magical, transformative powers. It is through the miracle of grace alone that our bodies retain any from today's deficient, over-processed meals. By grace, Cheetos are transformed into carrot sticks. By grace, Mountain Dew becomes actual dew from a mountain. By grace, our wheat-filled diet does not give us cancer. Amen.

Anglicanism
While Anglicans adhere to many of the mystical means of grace of Catholics, they're generally less strict. For example, while many Anglicans practice the sacrament of confession, they do not believe it results in the absolution of sin. Anglicanism contains many movements, some of which are quite Catholic, and some of which are almost evangelical in their understanding of the means of grace. Anglicans are usually content to tolerate a wide range of beliefs, so doctrines may vary.

Catholicism
Catholics believe in lots and lots of means of grace. These include reading the Bible, performing the many sacraments, prayers, and good works. Physical objects like the Rosary, ash, palms, and holy water can also be means of grace. Even the Church itself is a means of grace! Excommunication can prevent you from getting the sacraments, which can lead to minor side effects like eternal torment.

Independent Baptists
Independent Baptists believe that all this popish nonsense about "sacraments" is just cover for works-based salvation, which leads straight to hell! The only way to obtain salvation is to fling yourself on the ground and beg for it. Once you pray the sinner's prayer, nothing can keep you out of heaven, not even blowing up an orphanage.

Although Independent Baptists exemplify the extreme of this view, most evangelicals would agree with the basic idea that sacraments are stupid.

Calvinism/Reformed theology
Reformed Christians believe that the means of grace include the Bible and the sacraments, but only the two sacraments they believe are real (baptism and communion). (Those crazy English Reformed also thought that prayer should be included.) If you're not elect, don't even bother trying to understand, just brace yourself for never-ending pain.