He is the son of Zeus and a mortal named Semele, though in some versions, his mother is either Persephone or Demeter. While Semele was pregnant, she was visited by a jealous Hera in disguise, who tricked her into demanding that Zeus show himself in his true form. However, Semele, being a mortal, was scorched instantly upon seeing Zeus in all his glory. Zeus, though, was able to save the unborn Dionysus by sewing him into his thigh.
Consorts & Children:
Through Aphrodite, he's the father of the Charites, or Graces, and Priapus, god of fertility.
Notable Stories Involving Him:
As the god of wine, it's said he can bring joy, ecstasy, and freedom from inhibitions, but that he can also be dangerous and unpredictable and can drive someone mad.
His attributes are the thyrsus, or fennel staff tipped with a pine cone, and the grapevine.
Dionysus Around the World:
His Roman counterpart is Bacchus, though he's also been identified with the Roman Liber.
SOURCES: Greek Mythology.com, Mythweb, Encyclopedia Mythica, & Wikipedia