Ordinary time is the longest liturgical season in the Catholic Church.  It is 33-34 weeks long and is broken into two stretches of time.  The first stretch runs from the end of the Christmas season until Ash Wednesday, and the second from the end of Easter until the beginning of Advent.  Ordinary time is signified by the color green as a symbol of growth.  The United States Conference of Catholic Bishops further explains the purpose of the season:

Ordinary Time is a time for growth and maturation, a time in which the mystery of Christ is called to penetrate ever more deeply into history until all things are finally caught up in Christ. The goal, toward which all of history is directed, is represented by the final Sunday in Ordinary Time, the Solemnity of Our Lord Jesus Christ, King of the Universe.

Ideas to Celebrate:

• Use green to decorate your home - for example: your tablecloth, napkins, or candles
• Use seasonal (spring, summer, fall, winter) items to decorate to remind yourself of the "growth and maturation" that is ongoing
• Pick a saint feast day or two each week to read about and celebrate
• Try a new form of prayer
• Consider taking out some of the extras in your day-to-day life and saving them for special feast days
  • For example, only have dessert on Sundays and solemnities
• Make a goal to reach by the Solemnity of Our Lord Jesus Christ, King of the Universe, keep working towards that goal just as we keep working towards Christ