8 precepts

In addition to the 5 precepts, serious Buddhists will try to practice the Eight Precepts (aññhasãla) at least on the New Moon and Full Moon days of every month. 
The precepts in Buddhism are not commandments, as the Ten Commandments in other religions, but rather moral guidelines to go by so that one may maintain a healthy practice for oneself and for not harming others. As one develops in the Dhamma, one finds that the Precepts grounds your practice and that one cannot waver and purposely break any of the Precepts.
In following these Precepts one gradually develops a respect for the life of others, for their property, their dignity, their right to know the truth and a respect for the clarity of one's own mind. The Buddha called the practice of these Precepts a consideration to others which creates love and respect and which is conducive to helpfulness, non-dispute, harmony and unity (A.III,287).
On another occasion he called virtue freedom-giving and conducive to concentration (A.III,132). He also mentioned that one of the most important benefits of practicing the Precepts is that one experiences the happiness of being blameless (D.I,70). 
The Eight Precepts are typically also practiced during intensive meditation retreats of one day or longer. Some lay Buddhists take the Eight Precepts as a training lifestyle for the duration of their life in a sort of semi-monastic life.
==The Eight Precepts in Pali and English==
1. Panatipata veramani sikkhapadam samadiyami
*I undertake the precept to refrain from destroying living creatures.
2. Adinnadana veramani sikkhapadam samadiyami
*I undertake the precept to refrain from taking that which is not given.
3. Abrahmacariya veramani sikkhapadam samadiyami
*I undertake the precept to refrain from sexual activity.
4. Musavada veramani sikkhapadam samadiyami
*I undertake the precept to refrain from incorrect speech.
5. Suramerayamajja pamadatthana veramani sikkhapadam samadiyami
*I undertake the precept to refrain from intoxicating drinks and drugs which lead to carelessness.
6. Vikalabhojana veramani sikkhapadam samadiyami
*I undertake the precept to refrain from eating at the forbidden time (i.e., after noon).
7. Nacca-gita-vadita-visukkadassana mala-gandha-vilepana-dharana-mandana-vibhusanathana veramani sikkhapadam samadiyami
*I undertake the precept to refrain from dancing, singing, music, going to see entertainments, wearing garlands, using perfumes, and beautifying the body with cosmetics.
8. Uccasayana-mahasayana veramani sikkhapadam samadiyami
*I undertake the precept to refrain from lying on a high or luxurious sleeping place.
(from Anguttara Nikaya 8.41)
==References==
*The Complete Book of Buddha's Lists -- Explained. David N. Snyder, Ph.D., 2006.
*http://www.thedhamma.com/
Category:Buddha's Lists