Today is the 61st National Day of Prayer. Here's a link for the official site for information and background history.
National Day of Prayer
Prayer should be a daily event, not just for specified days. I'm always humbled by Paul's devotion to prayer as a major part of his life. There is power in prayer. I know that I've personally experienced that amazing power and continue to offer daily prayer for God's blessings and guidance.
Don't know what to pray or how to pray? .....
In the same way, the Spirit helps us in our weakness. We do not know what we ought to pray for, but the Spirit himself intercedes for us through wordless groans.