"Observe the Sabbath day by keeping it holy, as the Lord your God has commanded you."
The Sabbath is easily one of the most neglected gifts of God. Our bodies were made to work and to rest. It is commanded for proper maintenance of our bodily functions. But the most important reason to take a Sabbath is not that it is good for us to do (which obeying all of God's commandments are), but because God himself does it.
The LORD God, who is always working (Jn 5:17), and does not in anyway need rest since he does not grow tired, rested after 6 days of creation. God made that seventh day Holy by setting it apart from every other day. It is a day to sit back and reflect on the goodness of God and of his creation and to do nothing apart from beholding and worshiping God so that we may truly live in his presence. And believe me, God is so big that you are going to need all the time you can get to behold him!
An entire day written into the cosmos and ordained from the beginning of time for rest, relaxation, peace, joy, and celebration and here we sit thinking of how to get ahead with the extra time. You'd think people would not need convincing to enjoy the sabbath made for them, but it was so bad God actually had to command us to relax and enjoy life.