Answer:
   
   Gates of the Seasons, the American Reform Movement's guide to the
   Jewish Year, views Shabbat as a unique Jewish contribution to
   civilization, and a central activity to surviving the forces of
   assimilation and corruption. As such, it calls out the following
   mitzvot for Reform Jews:
   
   A-1
          The Mitzvah of Shabbat Observance
          
          It is a mitzvah for every Jew, single or married, young or old,
          to observe Shabbat. The unique status of Shabbat is
          demonstrated by its being the only one of the holy days to be
          mentioned in the Ten Commandments. ... Shabbat observance
          involves both positive and negative mitzvot, i.e., doing and
          refraining from doing.
          
   A-2
          The Mitzvah of Joy 
          
          IT is a mitzvah to take delight in Shabbat observance, as
          Isaiah said, "You shall call Shabbat a deligh". Oneg implies
          celebration and relaxation, sharing time with loved ones,
          enjoying the beauty of nature, eating a leisurely meal made
          special with conviviality and song, visiting with friends and
          relatives, taking a leisurely stroll, reading, and listening to
          music.
          
   A-3
          The Mitzvah of Sanctification 
          
          It is a mitzvah to hallow Shabbat by setting it apart from the
          other days of the week. ... Shabbat must be distinguished from
          the other days of the week so that those who observe it may be
          transformed by its holiness.
          
   A-4
          The Mitzvah of Rest 
          
          It is a mitzvah to rest on Shabbat. However, Shabbat rest
          (menuchah) implies much more than refraining from work. The
          concept of Shabbat rest includes both physical relaxation and
          tranquility of mind and spirit. On Shabbat, one deliverately
          turns away from weekday pressures and activities.
          
   A-5
          The Mitzvah of refraining from work
          
          It is a mitzvah to refrain from work on Shabbat...Abstinence
          from work is a major expression of Shabbat observance; however,
          it is no simple matter to define work today. Certain activities
          that some do to earn a living, others do for relaxation or to
          express their creativity. Clearly, though, one should avoid
          one's normal occupation or profession on Shabbat whenever
          possible and engage only in those types of activities that
          enhance the joy, rest, and holiness of the day.
          
   See Gates of the Seasons for additional details. Note support for
   Shabbat is also in the [5]1999 Statement of Principles
   ([6]http://www.ccarnet.org/platforms/principles.html), which says:
   
     We bring Torah into the world when we seek to sanctify the times
     and places of our lives through regular home and congregational
     observance. Shabbat calls us to bring the highest moral values to
     our daily labor and to culminate the workweek with (kedushah),
     holiness, (menuchah), rest and (oneg), joy.