Rosaries

rosary

In Catholicism, a rosary is a "crown of roses" that is used to pray to the Virgin Mary. It is called a crown of roses because catholics believe that each time they say a Hail Mary they are giving her a beautiful rose and that each complete Rosary makes her a crown of roses. The rose is the queen of flowers, and so the Rosary is the rose of all devotions and it is therefore the most important one. It is considered to be a perfect and humble prayer, like the Virgin Mary is. It is used to commemorate the events of Jesus's life. The way you use this for prayer is:

1. Make the Sign of the Cross and say the "Apostles' Creed."
2. Say the "Our Father."
3. Say three "Hail Marys."
4. Say the "Glory be to the Father."
5. Announce the First Mystery; then say the "Our Father."
6. Say ten "Hail Marys," while meditating on the Mystery.
7. Say the "Glory be to the Father."
8. Announce the Second Mystery; then say the "Our Father." Repeat 6 and 7 and continue with Third, Fourth and Fifth Mysteries in the same manner. (taken from here) 

People pray the rosary, usually, after a confession. It is not considered to be a punishment, rather a form of penance, where the person can reflect on their spiritual sin and grow from this.