In ancient Roman religion, the Epulum Jovis was a sumptuous ritual feast offered to Jove on the Ides of September (September 13) and a smaller feast on the Ides of November (November 13). It was celebrated during the Ludi Romani ("Roman Games") and the Ludi Plebeii ("Plebeian Games").Another description of the proceedings, this from The Roman Festivals of the Period of the Republic by William Warde Fowler:
The gods were formally invited, and attended in the form of statues. These were arranged on luxurious couches (pulvinaria) placed at the most honorable part of the table. Fine food was served, as if they were able to eat. The priests designated as epulones, or masters of the feast, organized and carried out the ritual, and acted as "gastronomic proxies" in eating the food.
........We may agree with the latest investigator of the Jupiter-cult that the origin of the epulum is to be looked for in a form of thanksgiving to Jupiter for preservation of the state from perils of the war season, and that no better date could be found for it than the foundation date of the Capitoline temple. This epulum was one of the most singular and striking scenes in Roman public life. It began with a sacrifice; the victim is not mentioned but it was no doubt a heifer, and probably a white one. Then took place the epulum proper, which the three deities of the Capitol seem to have shared in visible form with the magistrates and senate. The images of the gods were decked out as for a feast and the face of Jupiter painted red with minium, like that of the triumphator. Jupiter had a couch, and Juno and Minerva each a sella (chair), and the meal went on in their presence.
That was then, this is now - today we content ourselves by celebrating International Chocolate Day (who knew?) Hey, at least we don't have to sacrifice a white heifer!