Apocrypha means 'hidden things' in Greek.
The Apocryphical books of the Bible fall into two categories:
texts which were included in some canonical version
of the Bible at some point, and other texts of a Biblical nature
which have never been canonical.
The Deuterocanonical Books of the Bible
are books which are included in some version of the
canonical Bible, but which have been excluded
at one time or another, for textual or doctrinal issues.
These are called 'Deuterocanonical',
which literally means 'the secondary canon.'
These are other apocryphal texts which never made it into any official
canon, which nevertheless shed light on the Bible and its history.
The Forgotten Books of Eden
A collection of OT pseudepigrapha, specifically:
The First Book of Adam and Eve
The Second Book of Adam and Eve
The Book of the Secrets of Enoch
The Psalms of Solomon
The Odes of Solomon
The Letter of Aristeas
Fourth Book of Maccabees
The Story of Ahikar
The Testaments of the Twelve Patriarchs
Testament of Reuben
Testament of Simeon
Testament of Levi
The Testament of Judah
The Testament of Issachar
The Testament of Zebulun
The Testament of Dan
The Testament of Naphtali
The Testament Of Gad
The Testament of Asher
The Testament of Joseph
The Testament of Benjamin
The Lost Books of the Bible
edited by Rutherford H. Platt, Jr. 
A collection of NT apocrypha and pseudepigrapha.
The Biblical Antiquities of Philo
translated by M. R. James 
An alternative pseudepigraphal narrative of the Hebrew Bible from Genesis through 1 Samuel, written in the first century C.E.
The Gospel of Thomas
Reputedly the writings of the apostle 'Doubting Thomas'.
This text purports to be a collection of the sayings of Jesus.
Traditionally Thomas was Jesus' twin brother.
This text shows strong Gnostic influence.
The Sibylline Oracles
tr. by Milton S. Terry .
The Sibylline books were oracular Roman scrolls; these are the pseudo-Sibylline Oracles.
There many similarities to early Christian writings,
and they were quoted by the Church Fathers.
The Book of Enoch
Translated by R.H. Charles 
An etext of a critical edition of the Book of Enoch. Enoch introduced such concepts as fallen Angels, the Messiah, the Resurrection, and others.
The Book of Enoch the Prophet
Translated by Richard Laurence 
An earlier and very influential 19th century translation of 1 Enoch.
The Book of Jubilees
tr. by R.H. Charles 
A text from the 2nd century B.C.E. which covers much of the same ground as Genesis, with some interesting additional details.
It may have been an intermediate form of Genesis which
was incorporated into later versions.
Slavonic Life of Adam and Eve
The Books of Adam and Eve
This is the translation of the Books of Adam and Eve from the
Oxford University Press Apocrypha and Pseudepigrapha.
The Book of Jasher
Excerpts from the Gospel of Mary
This fragment, of disputed authenticity, puts the relationship between Mary Magdalen, Jesus and the Apostles in a radically different perspective than traditional beliefs.