I once saw a bumper sticker declaring April 1st as National Atheists Day. I didn't get it until I saw the verse referenced at the bottom: Psalm 14:1
"The fool says in his heart, 'There is no God.'"
If you are looking for a verse to memorize, that might be a fun one to learn for April Fool's Day.
Here is my verse for this time around.
Megan L. from San Marcos: "Therefore, since we are surrounded by such a great cloud of witnesses, let us throw off everything that hinders and the sin that so easily entangles, and let us run with perseverance the race marked out for us. Let us fix our eyes on Jesus, the author and perfecter of our faith, who for the joy set before him endured the cross, scorning its shame, and sat down at the right hand of the throne of God. Consider him who endured such opposition from sinful men, so that you will not grow weary and lose heart." Hebrews 12:1-3