The three days following Christmas are dedicated to martyrs of every stripe - the Innocents who died at the hand of Herod (martyrs "in deed"), St. John who willingly suffered for the Gospel but who died in exile and not violently (a martyr "of will"), and St. Stephen who willingly offered up his life for the opportunity to call Israel to repentance (a martyr "of will and in deed").

These days are also interesting for their significance to parish servants as they are the patrons of deacons, parish priests, and choir boys.

Many customs attend these ancient feasts - the best resource for learning about these is Handbook of Christian Feasts and Customs by F. X. Weiser - which can often be had quite cheaply in online bookstores.

Of course, full propers for all these feasts are included in Daily Divine Service Book, which you can still purchase with up to 20% off with various coupon codes listed here.