Hecate's Wheel is a symbol used by some traditions of Wicca. It seems to be most popular among feminist traditions, and represents the three aspects of the Goddess -- Maiden, Mother and Crone. This labyrinth-like symbol has origins in Greek legend, where Hecate was known as a guardian of the crossroads before she evolved into a goddess of magic and sorcery.
According to fragmentary texts of the Chaldean Oracles, Hecate is connected to a maze which spiraled around like a serpent. This maze was known as the Stropholos of Hecate, or Hecate's Wheel, and refers to the power of knowledge and life. Traditionally, a Hecate-style labyrinth has a Y in the middle, rather than the typical X shape found at the center of most labyrinths. Images of Hecate and her wheel have been found on first-century c.e. curse tablets, although there seems to be some question about whether the wheel shape itself is actually Hecate's domain or that of Aphrodite - there was some occasional overlap of goddesses in the classical world.
Hecate is honored every November 30 at the festival of Hecate Trivia, which is a day that honors Hecate as a goddess of crossroads. The word trivia refers not to miniscule bits of information, but to the Latin term for a place where three roads meet (tri + via).