The term Ordinary Time can be misunderstood when we talk about it in the sense of the Liturgical Year of the Church. It does not mean usual or average, it means not of a season. We have just completed the Seasons of Advent and Christmas and there are also the Seasons of Lent and Easter.
Ordinary Time is in two parts. The first part is the season we are in now, it begins the Monday after the Baptism of Our Lord and goes through the Tuesday before Ash Wednesday. The second part begins the Monday after Pentecost and ends the Saturday befor the first Sunday of Advent.
In Ordinary Time the Church celebrates the mystery of Christ., but not in a certain aspect as we do during the Advent/Christmas or the Lent/Easter Season. Though the readings during Ordinary Time we learn to live our Christian Faith through our daily lives. That does not sound "ordinary" when we look at the word in that context does it?
Green is the color of Ordinary Time, it symbolizes a sign of hope.