Catherine of Simple Kids has a list of questions you can use to interview family members. Then she included photos of significant times in each family member's life and put it all together in a hardbound book.
This also strikes us as a great activity for older kids to work on on Thanksgiving when relatives are all together anyway. Give them the questions and let them do the interviewing. What is just a fun activity now will become a cherished keepsake many years from now.
Thanks for the idea Simple Kids!