J.F.
That sounds like so much fun! Every year my sister does a scavenger hunt for the kids. She puts clues on 3x5 cards and each clue takes them to the next. The kids (and adults too) LOVE IT!
She also has a craft for kids (and adults who are interested). It is usually something simple but that can be personalized (i.e. ornament, graham cracker house, sugar cube house).
Good luck and Merry Christmas.