"Contrive" means to invent. All holidays are human inventions. Even in its original meaning as sacred time, a holiday is the product of human invention, not divine.
I fail to see the point you are making. The "holidays" below--if indeed they are sacred days at all, which I find doubtful--are all invented.
>Not all holidays are "contrived". Consider the following:
[snip]
Kevin R. Hardwick, Ph.D.
Department of History
James Madison University