The Gratitude Project stems from the first lesson of the Habits of Happiness lesson where Rick Warren talks about being grateful to the people in you life for who they are and for what they have brought you.
One of the assignments we had that day was to write down 5 things we were grateful for about the people closest to us. I extended that a step further by challenging people to actually GIVE a letter or note to that person with what they had written and then see how their relationship unfolds.
I'm completing my end of the challenge here with the letters I've written to the people around me. I'll try to do at least one a week on the Sabbath.