Recently I came across this thought of the four Chaos gods as season:
Tzeentch - Spring - Birth and rebirth and renewal. Planting, flowering.
Slaneesh -Summer - Flowering and fruiting, nurturing
Nurgle - Autumn - Harvest. and preserving, drying, decay
Khorne - Winter - subsiding, dying, hibernating, darkness
I can then plug the chaos gods into Gaelic and other pagan mythology for inspiration and ideas. For example the events: Samhain, Imbolc, Beltane and Lughnasadh.