Some good themes for a Christian retreat include "Faithbooking: Telling Your Story" and "A Holy Banquet for Hungry Hearts." Both of these themes found at HolyPath.org are ideal for a single-day or a week-long retreat.
The "Faithbooking: Telling Your Story" theme centers around the scripture of Deuteronomy 4:9. The goal of this theme is for retreat members to reflect and recognize God's hands in their lives. By seeing this and recognizing it, they come to grow in the word of God when they recognize how much God has done already.
The theme of "A Holy Banquet for Hungry Hearts" utilizes John 15:4. When church members lead busy lives, they yearn for deeper relationships with God. This retreat explores ways to reach this deeper level and balance daily demands.