The 1st of April- April Fool's Day. the origins of this festival are unknown. This is the day when practical jokes can be played with inpunity up until twelve of course! Along with all the silly chants; pinch punch first of the month!
There may be a link with Lud,a Celtic god of humour whose festival occured during spring, most of our festivals seem to originate from the Celts. The May Day festival is the day of Beltane, when the Celts marked the beginning of  summer with great bonfires in honour of the sun. Greenery and flowers were collected from the woods and hedge rows to decorate homes. This was the method of ritually conveying the fertilising powers of nature into the community. The May day rites have their origins in the fertility ceremonies which includes the crowning of the May Queen, dancing around the maypole( which I did as a child, must have worked I have four children!) morris dancing and plays.