1) God completed creation. 2) God took the Israelites out of Egyptian slavery (Exodus ch.20, Deuteronomy ch.5).
There is no Biblical reason, but it is a custom, as a symbol to 'remember' the significance of Shabbat, and to 'keep' the laws of Shabbat, which are two things the Torah tells us to do on the seventh day of each week.
Shabbat is very important because it gives you a chance to rest. In Rabbinical Times, the sabbath (Shabbat) was important for everybody, because everybody worked every other day. Shabbat is also a time for connection to God, and to find spiritual meaning, as well as a time for family and friend to get together. Me, being Jewish, and many Jews find that Shabbat is a great time to go over the weeks' events and to remember who you were kind to, and who you weren't.
The Shabbat is a subcategory of sacred, since God sanctified it (Genesis 2) as one of the the sacred things.
G-d did not create anything new on Shabbat; the 7th day of rest. All of creation was completed in the first 6 days of creation. Since then G-d has been maintaining the world, but not creating anything new. To commemorate this, Judaism defines 39 categories of creative work which are forbidden on Shabbat. E.g.: baking, planting and lighting fires. See http://www.answers.com/topic/39-categories-of-activity-prohibited-on-shabbat for an introduction to these 39 categories.
Because of the two different phrases (Zachor and Shamor) in which the Torah tells us to observe the Sabbath (see Exodus ch.20 and Deuteronomy ch.5). We light two candles to remember these commandments throughout the sabbath day.
Anything but a list of 39 prohibited acts. In the Talmud, tractate Shabbat, 12:1 it summarizes the spirit of the law as "one who does work on Shabbat and the work is enduring has violated shabbat." So, recreation, eating, worship, argument, all those are OK, but don't make things, plant things, harvest things, carry things (outside of your private domain), light fires, or put out fires (except to save a life). Saving someone's life on Shabbat is, of course, permitted even if it takes work.
Record and Commemorate
Commemorate is a verb meaning to remember or honour. It is often used in reference to people who are dead, but it is possible to commemorate other things, perhaps an event or period in time for example.This monument commemorates all those who lost their lives in the two World Wars.
Traditionally, the Shabbat candles are lit by women. If the woman is unmarried, she will usually light one candle, if she's married two and often one for each child.
MY AWNSER IS:=Computers, Electrical Items And Public Transport.=
In the Israeli military only necessary actions are done on Shabbat.There are no training, but if there are things that have to be done (like patrolling in the borders) they are done on Shabbat. This is ok because it is "Pikuach Nefesh" (peoples' lives will be in danger if the military will not guard them on Shabbat).