Phil 4: 6 Do not be anxious about anything, but in every situation, by prayer and petition, with thanksgiving, present your requests to God. 7And the peace of God, which transcends all understanding, will guard your hearts and your minds in Christ Jesus.
I LOVE this activity. We always used to do this at the end of our youth retreats. You tape a piece of cardstock to the back of each person. Everyone gets a pen and you walk around the room writing nice things about that person (like their great attitude, how they are a role model, or how you've seen them grow during retreat!)