St. John Bosco had a particular devotion to Our Lady under the title of Mary Help of Christians. He founded, in fact, the Salesian Sisters, also known as the Daughters of Mary, Help of Christians under her patronage. In his words: The principal objective is to promote veneration of the Blessed Sacrament and devotion to Mary Help of Christians. This title seems to please the august Queen of Heaven very much.
The fascinating history of the institution of this feast can be found here.
Some more good reading for the day: some exerpts from The Glories of Mary, by St. Alphonsus Liguori.
Prayer To Mary, Help of Christians
Thou, O Mary, art the Help of each Christian soul, as well as of the entire world. That same enemy who is bent on the destruction of the whole human race, is seeking to drag each one of us into perdition. He hates the image of thy Son, which he sees reflected in our human nature. Oh! come to our assistance; save us from this roaring lion of hell. He knows thy power, and that thou canst procure our deliverance, so long as we are left in this present life. Thou hast gained the most stupendous victories for the salvation of thy clients; tire not, we beseech thee, in aiding poor sinners to return to their God. When Jesus spoke of them that were invited to the marriage feast, and told us how the king said to his servants: Compel them to come in,* it was thee that he had mainly in view. Lead us then to our King!
~ Taken from the longer prayer on the feast of Mary, Help of Christians in The Liturgical Year, by Abbot Hueranger, O.S.B., Pascal Time - Book II
* St. Luke xiv 23