My good deed is volunteering as a field hockey coach every summer and working with elementary school age girls. They usually have no other opportunity to play during the school year and this is their only chance. I like to make the most of the experience for them and make sure they have the best time possible.
I'm participating in The No Evil project because I believe that this world would be a better place if we all did at least one nice thing a day for someone else, without expecting a return. This could be something as small as holding the door all the way to donating blood. Any act of kindness will be fully returned and when you're on the receiving end, it makes your day.