We were taught that Christmas is Jesus's Birthday and that day is to be celebrated as such. However, in our actions to me it was just another Sunday. Many Christmas's as a young child we never had company or went visiting on Christmas. We spend the day at home like any other in-between (since the Amish only have church every two weeks we had in-between Sundays) Sunday. My mother would read (silently) the bible or the Budget (Amish newspaper) and we usually played games. The only present we sometimes got was one board game for the whole family.
One year when I was in 3rd grade I think we got a Monopoly game so then we played that all day. My Father loved Monopoly and he was able to win most of the time. Other board games we had were Aggrivation, Chinese Checker, The Game of Life, and Upwords. The only card game we were allowed to play was Old Maid, Go Fish, and Uno. Many Amish do play cards for a pass time but my parents did not like playing cards. In our young folks group we played Rook quite a lot.
For the most part I know that many families got together on Christmas and exchanged gifts but we lived far away from any immediate family and my grandparents had all passed so we never had any place to go on the Holidays. The only other difference from everyday life is that my sisters and I would make some special treats (recipes that were too expensive in everyday life) like: rice krispie bars, chocolate covered pretzels and coconut bon bons. I also remember baking extra pies and breads so we could give some to the neighbors. I really enjoyed that because I knew the neighbors loved my baking.
In school we celebrated Christmas a little different. We colored Christmas pictures to hang in the windows or on the wall, we made paper chains to hang from corner to corner with a colored bell in the middle. I don't know why decorating was allowed in school but not at home. However, I also know that the extent of the decorating at school depended on who the teacher was. Sometimes the parents would complain on how much decorating was done at school.
At school we also exchanged names for gifts. The gifts were supposed to be fairly inexpensive because like my family, at one point there were 7 children going to school. A couple of days prior to Christmas we had our program. For that day we invited all the parents who brought food for the potluck. Once everyone got to school then we performed our program which consisted of singing Christmas songs and reciting poems. Then lunch was served and after that one of the dad's would play Santa (no costume) and hand out all the gifts to the students. When everyone had opened their gifts the children would go home with their parents and Christmas vacation began and lasted until the 2nd day after when normal school would resume.
I hope this helps you to understand how the Amish celebrated Christmas.