Here are some resources that may help you with this project:

Kathy Cassidy shared 2 projects which she has done on traditions and rituals:
http://kcassidy.wikispaces.com/traditions
http://kcassidy.wikispaces.com/rituals

Jennifer Wagner has a wonderful ning that lists other collaborative projects. (Thank you for posting our project!)
http://globaleducation.ning.com/

Thank you to Kathy Cothran for sharing this project through her mailing list. Kathy has a variety of resources, including holiday resources for teachers, listed at her web page:
http://technologylessonsforteachers.com/

Article on Holiday Traditions: http://edsitement.neh.gov/monthly_feature.asp?id=83