Category listing of recurring Evony events (19 posts), no single timing table given here (see each event's own page for cadence): Bacchus Tavern; Gladiator's Trial quiz; Revelation of Horus; Triumphal Celebration; Hecate's Moon; Battlefield/Clash of Civilizations (CoC); Clash of Civilizations Assault (Shadow of Dawn); Lucky Composing; Treasure Hunt (Pyramid, ~10 days); Revelation of Maya; Alliance Competition (~10 days); Crazy Eggs; Dwarf's Lucky Apple; Arctic Barbarians Invasion; Cleopatra's Treasure; Consuming Return; World Boss; Dawn of Civilization/Monarch Sciences (~10 days, ~2x/month); King's Party/Royal Party (~10 days, ~2x/month); Kill Event (KE). Most limited-time events run about 10 days and several recur roughly twice a month; a bot should track each event's own start/end rather than assume a fixed shared schedule.
Original research source: Evony Guide Wiki