Hi cbisch, by "good turn" I'm assuming you mean an unrewarded act of kindness, is that correct? If that is the case there's many great activities to encourage such integrity in children.  
 
One option is to look into youth groups that focus on such high moral standards.  Certain organizations often foster such "good turn" mentality such as the boy/girl scouts of America, or any local community centers such as the YMCA.
 
Aside from formal organizations, here are a few ideas off the top of my head:
-Volunteer  with churches, charities, etc.
- Food drives, unicef fund raisers
- Going for walks/hikes/bike rides while collecting and recycling trash
- Sports or games which emphasize teamwork and camaraderie
 
Also, depending on age, always consider the messages your children are taking away from movies, books, games, etc. I can personally say that the majority of my "good turn" beliefs come from bedtime stories of King Arthur and other chivalrous knights told to me by my parents.
 
http://www.goodturnforamerica.org/
http://www.inquiry.net/ideals/deeds/index.htm

Hi, Here are some additional craft activities you might consider (depending on the age and interest of the children)...
 
Make a Tissue Paper Bouquet -- to brighten someone's day
http://www.education.com/activity/article/tissuepaperbouquet_first/
 
Go Green: Turn T-Shirts into Totes -- to teach environmentalism & resourcefulness
http://www.education.com/activity/article/Green_Turn_Tee-Shirts_into_Totes/
 
Invent Your Own Chore Helper! -- to bring helping home
http://www.education.com/activity/article/chore-inventions/
 
Give Birds a Feast with This Suet Feeder -- to be kind to animals
http://www.education.com/activity/article/give_birds_a_suet_feast/
 
Give Your Next Gift in a Treasure Box! -- to make it extra special
http://www.education.com/activity/article/Kindergarten_treasure_gift_box/
 
And here are some ideas beyond crafts, to teach children how to pass on a good turn...
 
Summer Volunteering 101
http://www.education.com/magazine/article/Volunteering/
 
Save Our Oceans: 5 Things Your Kids Can Do
http://www.education.com/magazine/article/Save_Our_Oceans_5_Things_Your/
 
Growing Kids Who Care
http://www.education.com/magazine/article/Growing_Kids_Who_Care/
 
Here's another idea too:
When I was a child, I participated in Girl Scouts. One 'good turn' thing we would do was make dry noodle necklaces or Popsicle-stick picture frames for seniors, and then go deliver the items and sing Girl Scout songs at the local elder living center. I remember the recipients being so grateful for the gifts, but really they seemed to enjoy our company most of all. That might be something you consider doing with your children as well.
 
Or contact your local animal shelter and see if your children can volunteer to walk the dogs. Or contact your local food bank and see if you can bring in a team of child volunteers to sort and package food for the needy.
 
All the best to you in whatever 'good turn' endeavor you and the children choose!

Just another thought, but many martial arts classes emphasize morals, integrity, and helping people. Look around your area (especially in community centers) as many dojos offer free intro lessons and a basic demonstration of what values they intend to teach your children.

Well I hope this is what you are looking for. My grand kids went with me to the local hospital pharmacy. While waiting the pink lady. came out and ask the kids if they wanted to look at the toys. The gift shop had allot of singing toys. They went in and got to listen to the toys and listen to the pink lady. and then she brought them back set them into a chair and gave each one a piece of candy. (with permission). She was very nice. We had to run another place and then go back to pick up the medicine. While we were at the store I explained to the kids that she was a volunteer. They were really interested that what she did she didn't get paid. so When we went back the kids each got her a rose and gave them to her. She was so happy and the kids got to learn about money is not what you always need but friendship and good manners could make someones day very bright. We could have made a craft but time was not with us. hope this story helps
KatStevens10