The end of April marks Walpurgisnacht, the northern European and Scandinavian celebration of pagan origins. Customs vary from country to country, but modern festivities commonly involve revelers dressed as witches feasting and dancing around bon fires to officially welcome spring, celebrate fertility and drive away evil spirits. Sounds like a good party!
Disney famously portrayed Walpurgisnacht in the Night On Bald Mountain sequence from Fantasia. I didn't even realize this until mumsy pointed it out... but I do remember the Demon scaring the pants off me as a kid!