Beltane is a Pagan esbat, celebrated most commonly on May 1st. It is primarily a fertility festival, celebrating union of the Goddess and the God, and through sympathetic magic also encouraging the fertility of the land.
Beltane is often celebrated with bonfires, which have dual meanings. Firstly they represent the sun and celebrate and encourage it’s increasing power in the run up to the summer and the important crop-ripening period of the year. Secondly they burn away the old and make way for the new, thus cleansing the soil and the spirit of any negative influences. See my entry on bonfires here.
Beltane is also celebrated with dancing round a Maypole. The fertility symbolism here is obvious! Men and women dance around the pole, wrapping it in red and white ribbons - Red here representing Feminine powers and White Masculine.
Key figures in the celebration of Beltane include the Green Man, the May Queen, the Oak King and fairies.