This article is from the Wicca FAQ, by firstname.lastname@example.org (Rain of Teleport) with numerous contributions by others.
Most Wiccans mark eight holiday "sabbats" in the "wheel of the year,"
falling on the solstices, equinoxes and the four "cross-quarter days" on
or about the first of February, May, August and November. The names of
the sabbats may differ between traditions, and many Wiccans also mark
"esbats," rituals for worship in accordance with a given moon phase (such
as the night of the full moon). Although there is no one source for all
Wiccan liturgy, many liturgical items such as the methods for casting the
circle, the "Charge of the Goddess," certain myths and formulaic
expressions are common to many traditions. Some common formulaic
expressions include "hail and welcome/farewell," "blessed be" (sometimes
abbreviated on the net as B*B) and the closing "Merry meet and merry part,
and merry meet again." There is no one bible or book of common prayer for
all Wiccans, however, and great value is placed on creativity, poetry and
the artful integration of different myths and ritual elements.