Notre Dame Online's December Theme is Advent-Christmas.
There are many printable and online resources available for age groups from toddlers to seniors.
Included here for your use are a few that stand out from the United States Conference of Bishops (www.usccb.org), a few Jesuit websites and a few new websites for additional ideas.
The United States Catholic Bishops offer the following Advent Resources
CFJ Advent Reflections
Dorothy Day Center for Faith & Justice
A Jesuit Ministry
This site also offers a Sacred Advent Retreat (from the Irish Jesuits), Advent Calendars, a downloadable The Jesse Tree PowerPoint Presentation, Daily Inspiration during Advent, and Prayers for Advent.
New: Teacher Resources
[ www.catholicteacherresources.com ]
(For full access school must belong... $295 yr.)
A ministry of Virginia Theological Seminary
[ https://buildfaith.org/free-resources-for-advent/ ]
Providing resources in Jesuit education and Ignatian Spirituality
[ https://www.xavier.edu/jesuitresource/resources-by-theme/advent-and-christmas-resources ]