IMO, the issue you run into there mongoose is that this is played by players all over the world. Therefore, there are holidays that each country celebrate. In to be fair all holidays of all countries and religions would have to be included. There would be so many, that knowing other countries holidays for every player would be difficult and confusing. I bet if you took a pool from every player that is registered right now. There would be so many dates blacked out on movement processing that even a simply game would take months to complete. Idea would be great if only one country was involved, but this is a world wide game. To give you an example, how many holidays, and when are they celebrated in Guam? How about India? Korea?