The following is from a comment made by Vanessa. I am posting it more prominently so we can all share her ideas.
One of the things that made Sabbath special for me as a kid was that my parents always interacted with us kids. We were not left alone to play "quietly." Instead, we spent the day doing something together. It was usually very simple, such as a hike/walk in which we collected things according to some theme, or on a rainy day we'd play a Bible game. I'm not sure it really mattered the activity, but more that my parents gave us alot of attention. (It also has given me a good illustration of how God wants me to lay aside my other responsibilities and focus my attention on Him.) I also have very fond memories of Sabbaths when several families would get together and sing and the kids would do charades of Bible stories. I have made it a priority to recreate this for my kids as much as I can. Tiredness can wait, FB can wait, dishes can wait, cooking might not be able to wait, but can be simpler ... I've also found several books helpful for ideas from books called "The Gospel According to a Tree, Snowflake, etc.... by Terry & Jean McComb. Website: www.GospelCreation.com
I've also discovered my freezer really helps me with time and energy on Sabbath, so I have more of both to give to my kids...and my husband. I never make less than 2 or 3 casseroles at a time, put them in the freezer. That way, I am always prepared for a few busy weeks, and we can still be hospitable. This works well for cookies and dinner rolls too, Also, I make cinnamon rolls about once every 2 months, divide and freeze. My family loves having Sabbath Cinnamon rolls and I have no stress!!! This has become a special Sabbath treat my whole family looks forward to Sabbath for.
I look forward to hearing other's ideas...