The enlightenment of the Buddha is among the most significant events in Buddhist history, and it’s an event commemorated annually by many Buddhists. English speakers often call the observance Bodhi Day. The word bodhi in Sanskrit and Pali means “awakening” but is often translated into English as “enlightenment.”
According to early Buddhist scripture, the historical Buddha was a prince named Siddhartha Gautama who was disturbed by thoughts of sickness, old age and death. He gave up his privileged life to become a homeless mendicant, seeking peace of mind. After six years of frustration he sat under a fig tree (a variety known ever after as a “bodhi tree”) and vowed to remain in meditation until he had fulfilled his quest. During this meditation he realized enlightenment and became the Buddha, or “the one who is awake.”
source http://buddhism.about.com/od/buddhistholidays/fl/Bodhi-Day.htm
How Can I Celebrate?
There are a few easy ways you can celebrate Bodhi day:
Tree & Lights: In many Mahayana Buddhist countries, they decorate their homes or ficus tree with multi-colored lights to signify the many pathways to enlightenment². Some even decorate their trees with shiny objects (typically three) to signify the three jewels³. This is a fun activity for children and the whole family. Be sure to start your multi-colored lights on 08 December, and keep them up for 30 days.Buddha Statue: If you have a Buddha statue, you might want to place it at the base of your tree. This can help symbolize the Buddha as he sat under the tree and gained enlightenment.Practice: For some Buddhists, we take the day to focus our commitment to the path by practicing longer meditation, performing acts of loving kindness for others, reading the Dhammapada, or chanting sutras.Precepts: Many Buddhists will recite the five precepts on Bodhi day to help reaffirm their belief and conviction towards the path.Food: You can even partake in a meal of milk-rice (click here for cooking instructions) that the maiden Sujata offered to the future Buddha when he was weak from not eating. This was a major turning point in helping him realize that the middle way is the only way.Children: A great way to get kids involved and explain about how the Buddha gained enlightenment (and what it means) is to have them bake cookies in the form of the leaves of the Bodhi tree (any ‘ficus’ style leaf shape will do just fine also).
The essential part of Bodhi day is to not only recreate some of the physical and symbolic things that helped the Buddha achieve enlightenment, but to plant and grow those seeds of enlightenment within yourself.
http://www.alanpeto.com/buddhism/bodhi-day/ link to Alan Peto’s website bodhi day page