The Sabbath is a special day in different religions. The Jews say that God created the world in six days and rested on the seventh, so they celebrate by ceremonially resting on Saturday as their Sabbath. Most Christian denominations celebrate it on Sunday, although a few observe Saturday.
Sabbath is celebrated in myriad ways. Based on the biblical prohibition against labor on the Sabbath, Orthodox Jews eschew anything that involves labor--for example, walking long distances, lighting a fire (which includes using electrical appliances), or spending money--between sunset Friday and sunset Saturday. Jews typically attend synagogue services, and Christians typically attend church services, on Sabbath. Some avoid secular activity for the entire day, and others engage in recreational activities once the church services are over, whereas many Christians and Jews observe no particular restrictions on the activities of the day.
Sabbath dinner is an important formal activity. This takes two primary forms: the family dinner and the potluck. For the family dinner, members of a household, and perhaps a few invited guests, gather for a shared meal at home after church; often, the family's finest dishware (not normally used the rest of the week) is employed. For a church potluck, each congregant or family contributes enough food to serve several people. After the services are over, everyone gathers to share the many foodstuffs that have been contributed. This reduces the amount of work any one person would have to do to prepare a meal for a large number of people. Large groups will often use disposable dishes and utensils. For a traditional potluck, there is no advance planning of the overall menu--a practice that hints at the origin of the word potluck: the luck of the pot, i.e. whatever food comes from the pot. However, many groups will specify some dietary restrictions, e.g. vegetarian dishes only.
Muslims also set aside time each week for sacred activity; however, the observance bears little resemblance to Jewish or Christian Sabbath observances. Muslims consider Friday the best day of the week, and will take some time each Friday for Jummah prayer, and afterward return to whatever else they were doing.