Tomorrow (January 1st), besides being for many the first day of the New Year (while the ecclesiastical New Year's Day is considered September 1st), are celebrated two great feasts of the Orthodox Church (the feasts of Christ's Circumcision and of St. Basil the Great). See below for St. Nikolai's account of the Circumcision of Christ (taken from: http://www.westsrbdio.org/prolog/January1.htm):
"The eighth day following His birth, the Divine Child was presented in the Temple and circumcised according to the Law existing in Israel since the time of Abraham. On this occasion, He was given the name Jesus [“Jesus” means “he who saves” (http://www.greekorthodox.org.au/general/spirituality/thejesusprayer)], which the Archangel Gabriel announced to the All-Holy Virgin Mary. The Old Testament circumcision was the proto-type of the New Testament baptism. The circumcision of our Lord shows that He received upon Himself the true body of man and not just seemingly, as was later taught of Him by heretics. Our Lord was also circumcised because He wanted to fulfill the entire Law which He Himself gave through the prophets and forefathers. In fulfilling the written Law, He replaced it with Baptism in His Holy Church as was proclaimed by the Apostle Paul: "For neither does circumcision mean anything, nor does uncircumcision, but only a new creation" (Galatians 6:15). (In the cycle of the liturgical calendar of the Church, this Feast of the Lord's Circumcision has neither a Forefeast nor an Antefeast)."
For more on St. Basil, one of the great Saints and Fathers of our Church, see: http://www.goarch.org/chapel/saints_view?contentid=364 , http://www.westsrbdio.org/prolog/January1.htm , http://www.ccel.org/ccel/schaff/npnf208.toc.html , http://www.orthodoxwiki.org/Basil_the_Great , http://ocafs.oca.org/FeastSaintsViewer.asp?SID=4&ID=1&FSID=100003
(taken from: http://www.goarch.org/chapel/calendar on January 1st)