Beltane — celebration of the conjoining of the goddess with the energy of the god in the sacred marriage which is the basis of all creation.

Imbolc -- reflection on the power of the gods from which physical and spiritual harvest will come.

Litha -- celebration of the sacred marriage in which energy of the gods is poured into the service of life.

Lughnasadh — Wicca/neo pagan observance of first harvest of the year involving agricultural festivals and prosperity magic. The Christian name of Lammas is sometimes used.

Mabon — observance of the autumnal equinox when day and night are of equal length. A harvest festival time.

Ostara -- welcoming of spring and the goddess-as-maiden.

Samhain — celebration of endings and beginnings and of remembering the dead. Revering of elders is also observed. 

Yule —  a Norse pagan celebration of the winter-born king, symbolized by the rebirth of the sun. A present day Wicca event. 

Imbolc.cerddwr, CC BY-SA 3.0, via Wikimedia Commons

Sept. 21-29 -- Mabon

Nov 1 -- Samhain (Starts at sundown the day before)

Dec 21 -- Yule (Starts at sundown the day before)

Feb 2 -- Imbolc

Mar 19 -- Ostara

May 1 -- Beltane