What about Ash Wednesday and Lent? Are they in the Bible? Why do some churches believe in these things?
First of all, they are not specifically found in the Bible as observed by modern churches.
Having said that, Ash Wednesday and Lent are Biblical practices. In Biblical times, putting on ashes and sackcloth were considered common practice for religious people as they prepared themselves for special occasions or when they practiced penitence for their wrongdoings, their sins, and as they were intentionally mindful of their need to be right with God.
He has told you, O man, what is good; and what does the Lord require of you but to do justice, and to love kindness, and to walk humbly with your God? Micah 6:8 ESV
And Abraham replied, "Now behold, I have ventured to speak to the Lord, although I am but dust and ashes." Genesis 18:27
No one can oppose you, because you have the power to do what you want. You asked why I talk so much when I know so little. I have talked about things that are far beyond my understanding. You told me to listen and answer your questions. I heard about you from others; now I have seen you with my own eyes. That’s why I hate myself and sit here in dust and ashes to show my sorrow. Job 42:2-6
Lent is the traditional forty days (plus Sundays) before Easter, starting with Ash Wednesday. Yeah, the math is a little odd, but that is the general idea and each Sunday is a celebration of the coming of Christ.
Forty is a significant number in the Bible and typically indicates a season of trial or testing. There was the Genesis rain and flood, Moses receiving the Law on Mount Sinai, forty years in the wilderness, Jesus' temptation in the wilderness, and many more. So a forty-day period of preparation -- fasting, worship, learning, and serving -- is both appropriate and biblical.
Easter is a great deal more than candy and bunnies. It is about the very present power of God in the midst of a world that rejects and denies its God and crucifies its Savior. And that power is "grace" as amazing as it is.
For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life. For God sent not his Son into the world to condemn the world; but that the world through him might be saved. John 3:16-17 KJV
Fasting, abstaining from food or drink in order to be more prayerful and seek Gods will, is a common practice during Lent. People may ask why missing some meals will help them be closer to God's purpose. Fasting is about denying the appetites and needs of the body in order to feed the spirit.
Years ago my Bible Study group decided to give up one meal each week during Lent and then take the money that meal would have cost and use it to help feed hungry children.
“Is it a fast like this which I choose, a day for a man to humble himself?
Is it for bowing one’s head like a reed
And for spreading out sackcloth and ashes as a bed?
Will you call this a fast, even an acceptable day to the Lord?
“Is this not the fast which I choose,
To loosen the bonds of wickedness,
To undo the bands of the yoke,
And to let the oppressed go free
And break every yoke?
“Is it not to divide your bread with the hungry
And bring the homeless poor into the house;
When you see the naked, to cover him;
And not to hide yourself from your own flesh?
“Then your light will break out like the dawn,
And your recovery will speedily spring forth;
And your righteousness will go before you;
The glory of the Lord will be your rear guard. Isaiah 58:5-8 NASB
Other Lenten observances have included discovering new places to volunteer andserve in the church and community.