From Access To Insight, "Uposatha days are times of renewed dedication to Dhamma practice, observed by lay followers and monastics throughout the world of Theravada Buddhism...On New Moon and Full Moon days...Lay people observe the Eight Precepts on Uposatha days." (see the full quote)
Today, for this day and night, I will abandon the destruction of life and abstain from it; with the rod and weapon laid aside, I will be conscientious and kindly and dwell compassionate towards all living beings.
Today, for this day and night, I will abandon the taking of what is not given and abstain from it, accept only what is given, expect only what is given, and dwell with honest heart devoid of theft.
Today, for this day and night, I will abandon incelibacy and live the celibate life, remote from sexuality, refraining from the coarse practice of sexual intercourse.
Today, for this day and night, I will abandon false speech and abstain from it; be a speaker of truth, adherent of truth, trustworthy and reliable, not a deceiver of the world.
Today, for this day and night, I will abandon wines, liquors and intoxicants which are the basis of negligence and abstain from them.
Today, for this day and night, I will eat only once and refrain from eating at night, from untimely meals.
Today, for this day and night, I will abstain from dancing, singing, instrumental music and unsuitable shows, and from adorning myself by wearing garlands and applying scents and ointments.
Today, for this day and night, I will abandon the use of high and luxurious beds and seats and abstain from them; make use of a low resting place, either a small bed or straw mat.