Lammas, or ‘loaf mass’, marks the time of the year that you begin celebrating the harvest season. August first celebrates one of three harvests, which include Lammas (Aug 1), Mabon (Sept 19-23), and ending with Samhain (Oct 31).
Celebrating the ‘first fruits’ of the year, Lammas includes a feast of thanksgiving, and honors the Sun/Harvest god(s) of the field. They days grow shorter, the nights lengthen as the Sun weakens in this waning half the year. Preparations of the colder months begin, and the holiday marks a time of bounty.
Many traditions mark this holiday:
Some sites including rituals for Lammas:
Moonshadow realm– Includes some nice pictures such as a beautiful homemade loaf of bread and some recipes you can make.
About.com Pagan/Wiccan – Includes links for crafts, recipes, and celebrations of Lammas.
Cyberwitch.com – Their page on Lammas is packed with Lammas traditions and history.