Every year, there is a monthly CFC theme provided by the sector/area. You can use this as your CPA/assembly theme.
Here are other possible themes / topics for Chapter Prayer Assembly:
January - First Fruits, Thanksgiving
February - Love
March - Spring, Lent, Gift of Life
April - Lent, Holy Week
May - Mothers' Day
June - Fathers' Day
July - Summer, Canada Day, CFC Conference, Family
August - Summer, ANCOP
September - Mary
October - Rosary, Mission, Thanksgiving
November - Saints, Advent
December - Christmas