All Gods' Eve is the most important festival for the kith of Morgrave. However, it does not lie on any calendar, instead the celebrations spontaneously erupt during a lunar eclipse, both on a partial one and especially on a blood moon. Kith in Morgrave don't have the best grasp of astronomy - they're not really seafaring and they haven't had many natural philosophers - even if some genius has figured out that the world is round, it hasn't gained any traction. So, when a great shadow comes across the moon they believe it's a divine phenomenon. They believe that the shadow is their gods attacking the outsiders, an evil race of creatures who live on the moon and invaded Morgrave long ago in pre-history. During a blood moon, it clearly means that the gods are setting fire to the outsiders' towns and castles, thus keeping them on the moon.
Celebrations on All Gods' Eve are sudden and chaotic. Since there is no advanced astronomy, no one knows when the next All Gods' Eve will occur and so everyone must be ready at all times. Since it only happens at night, all towns and villages are required to have someone watching the moon throughout the entire night. Once this spotter sees the eclipse, they ring the Gods' Bell and people stream into the streets to see the moon. The towns keep celebration materials on hand at all times - food, alcohol, and a wicker man effigy of an outsider that they burn. People stay up all night celebrating and the next day is called off as a holiday.
Mountain Dwarves have the hardest time of this. Normally a dour lot, they celebrate just as hard as the rest of the kith on All Gods' Eve, but their cities lie deep under the mountains, usually. The Mountain Dwarves still use a spotter outside the mountain. When they spot an eclipse, they ring a bell, and another Dwarf further down the entrance of the mountain relays another bell to another Dwarf even further down the mountain - the bell equivalent of a fire relay. Eventually a Dwarf in the heart of the mountain city rings the Gods' Bell, but by the time the Dwarves stream out of the mountain to see the eclipse, its usually over. Still, that doesn't stop them from celebrating out under the night sky; it's one of the few things capable of getting a Mountain Dwarf to leave their mountain.