warning...semi rant ahead...
First of all, I will make myself clear. If you spent today in prayer, alone or in the community of others, I respect that. And in the U.S. and a lot of other nations, we are fortunate to live where the act of prayer is allowed, even encouraged, and not driven underground.
That said, I do not feel it is the business of our government to go about promoting prayer. As much as I feel it is not the business of our government to promote meditation, yoga, Tai Chi, reading "Chicken Soup for the Soul" books, dancing naked around a bonfire, or any other practice that suggests spirituality.
I am not a praying person. I always felt strange petitioning some father figure Up There, who already was supposed to know my needs and have some Divine Plan for me, with my own needs and wants of the day. I learned at an early age that we do not always get what we pray for. So why pray? But if it brings you peace, that is good.
I would rather see a "National Day of Reconciliation". "National Day of Talking To Your Neighbors". "National Day Where Hate Is Forbidden". "National Day of Tearing Down Walls". Prayer is easy. Action, not so much.
You may say I'm a dreamer... but am I the only one?