- No killing.
- No stealing.
- No sexual misconduct (or no sex at all).
- No lying (or deceptive / manipulative speech).
- No drinking (alcohol; can be expanded to include non-prescription drugs and smoking).
- Only eat after sunrise but before noon.
- Abstain from singing, dancing, playing music, attending entertainment performances, wearing perfume (deodorant?), and using cosmetics and jewelry.
- No sleeping or sitting on comfortable furnishings; no long naps.
I've been lax about actually following some of these precepts. I'm sure Buddha didn't want health issues to be exacerbated by fasting or by sleeping / sitting on a hard surface. #3 & #5 conflicts with my Pagan practice. However having vegetarian meals once a week won't kill me. Instead of doing the things mentioned in #7, time should be spent in meditation and study of Buddhist teachings.
Several Full Moon Uposatha days hold special significance. For example, Vesak is May's full moon which celebrates Buddha's birth, awakening, and death.