Here is a large list of things that many folks believe are true but either aren't true or are mostly untrue.
http://en.wikipedia.org/wiki/List_of_common_misconceptions
I had thought until recently that the Immaculate Conception referred to Jesus' virgin birth. It doesn't. But according to this, it also doesn't refer to Mary's virgin birth (which I don't believe in) either. It refers to the belief that Mary was not subject to original sin from the first moment of her existence, when she was conceived. Of course there is no scriptural support for this, it is fabrication by early Catholics.
