Bastet was the formal name of a benevolent egyptian goddess of music and mother to all cats everywhere - also known as just Bast, The Tearer. She carried around a little musical instrument called a sistrum which was supposed to ward off evil spirits. She was a daughter and wife of Ra, and mother to Maahes, Nefer-Tmu and Khensu. Some reports say she was also known as a goddess of fire, fertility, sexuality and childbirth, the Moon, protection against disease and evil spirits, and intuition. She was usually depicted as a dark-furred humanoid female with a domesticated cat's head, garbed in an emerald gown.

The cat was viewed as a most sacred animal by Egyptians, but the black cat was especially sacred and a symbol of healing in their culture. Cats were kept in Bast's temple and even embalmed after death. Her cult appeared around the time of the second dynasty. The most famous place of Bast worship was located in Bubastis, known today as Tell Basta, in the Delta. In her dark aspect, Bast was also known as Pasht. She was identified with Artemis and Diana from greek and roman mythology respectively, who were also called 'the mother of cats.'

How do I know this? Benefits of a pagan ex-wife who studies Egyptian mythology. =) Bast was also a featured character in the Sandman comic book series. She and Morpheus the Lord of Dreams used to tussle under the covers and he visits her again a bit before her death. Further, randombit pointed out to me that, "she also shows up (and gets it on) a bit in American Gods."