Yet another interpretation, popularized as a part of the conspiracy theories of Micaheal Baigent and Richard Leigh in Holy Blood, Holy Grail, was that Barabbas was the actual son of Jesus and Mary Magdalen. In their reading of the Story of Jesus, Jesus was crucified for claiming the literal title of King of the Jews because of his descent (through Joseph) from King David, and the mobs clamored for the release of Jesus Barabbas because he was, literally, "the son of the father", and the line of Jesus might be continued.
The evidence they give, while mostly circumstantial, is compelling, at least if one is already sympathetic to conspiratorial readings of the Birth of Christianity. Barabbas is described in the Bible with the greek word lestai, which literally means bandit, but at the time was used as a euphemism for the Zealots who roamed the Judean countryside fighting for independence from Rome. Jesus Barabbas' sobriquet Barabbas is a shortened form of the Aramaic Bar Rabbi, which means "son of the rabbi".
Now, in the Bible, Jesus is in fact accorded the title rabbi, which has a literal meaning closer to "teacher". However, under the laws of the time, a man could not be considered a rabbi unless he had already married and fathered a child. This seems to be supported by certain of Gnostic Gospels, which imply a "special relationship" between Jesus and Mary Magdalen. Under this reading, it was Jesus who was married at the Wedding at Cana, which is supported by a guest telling him (I paraphrase here) "normally one doth give the best wine at first, and the worst as the night wears on, but thou has saved the best for last." Under the customs of the time, it was the responsibility of the groom to provide the provisions, such as wine, for a wedding.