Holiday's

The "twelve great feasts," as they occur in chronological order after September 1, are as follows:

The Nativity of the Virgin Mary (September 8)
The Elevation of the Life-giving Cross (September 14)
The Presentation of the Virgin Mary in the Temple (November 21)
Christmas (December 25)
Epiphany (January 6)
The Presentation of Christ in the Temple (February 2)
The Annunciation (March 25)
Palm Sunday (the Sunday before Easter)
The Ascension (40 days after Easter)
Pentecost (50 days after Easter)
The Transfiguration (August 6)
The Repose of the Virgin Mary (August 15)

(http://www.goarch.org/en/ourfaith/articles/article7070.asp)