Happy May Day, no matter how you celebrate it:
In the Roman Catholic tradition, May is observed as Mary’s month, and May Day is usually a celebration of the Blessed Virgin Mary. In this connection, Mary’s head (in works of art, school skits, etc.) will often be adorned with flowers.
or
The maypole is a tall wooden pole (traditionally of hawthorn or birch), sometimes erected with several long colored ribbons suspended from the top, festooned with flowers, draped in greenery and strapped with large circular wreaths, depending on local and regional variances.
or (my preference):
In addition, May Day in the United States is commonly regarded — at least by certain groups* — as a commemoration of the execution of the Haymarket martyrs who were arrested after the Haymarket Riot of 1886 in Chicago, Illinois, which occurred on May 4, but was the culmination of labor unrest which began on May 1. The date consequently became established as an anarchist and socialist holiday during the 20th century, and in these circles it is often known as International Workers’ Day or Labor Day. In this form, May Day has become an international celebration of the social and economic achievements of the working class and labor movement.
*That’s Wiki code for “pinkos.”