The real answer, however, is far more complex than that. To begin with, there is no such thing as a religion called Judaism. Judaism is a civilization, in which religion is one of its many dimensions. There is also a tradition of an Oral Torah, which was written down around the time of Christ as the Talmud. There are varying degrees to which Jews give authority to Torah and follow is practices.
Some practices are common to all.
Many Jews follow the dietary laws called out in Lev. Jews observe the Sabbath from Friday Night to Saturday night, as well as a large variety of holy days during the year.