Ixion, the lightning-element Aeon from Final Fantasy X, derives somewhat from a figure in Ancient Greek mythology by the same name.
He was a king with a reputation for being a bit of an asshole. Zeus showed Ixion mercy after he murdered his own father-in-law, and invited him to a feast on Mount Olympus. There, Ixion made the grave mistake of trying to seduce Hera, Zeus' wife and queen of the gods.
To teach him a lesson, Zeus fashioned a fake Hera out of clouds (he was the storm god, after all), and she was called Nephele. Ixion slept with Nephele, and their son was Centaurus, a deformed boy who made love to horses. Centaurus' half-man-half-horse offspring were the centaurs, also known as the Ixionidae based on their lineage.
The association of FFX's Ixion with lightning would presumably be with regards to Zeus' role in the story. The sky god's weapons were his lightning bolts, the equivalent of which in Norse mythology was Thor's hammer, Mjolnir. This is why (random as it might otherwise seem) Ixion's Overdrive move in battle is Thor's Hammer.