Christmas day in Marrakech is an interesting experience. Almost everything is open as usual. The businesses that are European owned and focused on European customers tend to be closed but everything else is business as usual.
Christmas 2014 saw 20 degrees. Warm enough to explore the city in summer clothing and take in lunch at one of the terrace restaurants overlooking the streets and squares of the city; sunglasses essential. One of the real bonuses is the "business as usual" culture meaning there were no christmas day menus with inflated prices. A simple lunch at a reasonable price.
The souks were open as usual. Something really decadent about Christmas shopping on Christmas day. Possibly not the most religious or spiritual way to spend Christmas day but definitely different. For the more religious there is the Catholic Church of L'Eglise des Saints Martyrs in the new city which has services during the Christmas period.
Again the evening can be spent in one of a number of restaurants. Both the simple restaurants and the more upmarket are open as usual.
The down side...Boxing day does not herald the first day of the sales.