When God saw the hopeless predicament of humanity -- that we were in bondage to sin and death -- He had compassion for us. Because of His love, He set in motion a plan to rescue humanity from spiritual destruction and offer life and hope.
Jesus Christ was sent from Heaven to become the door through which we can be "saved" (to use a church term) from the curse of sin. He accomplished this task by dying on the Cross as a substitute sacrifice, bearing the penalty for our sins. The Bible clearly says: "The soul that sins, it shall die." Since none of us is perfect (all of us prove this by our pride, lust, selfishness, greed, bad language, anger, bitterness, etc.) than all of us are separated from God and on the road of death. However, Jesus was perfect -- the Bible tells us that He never sinned even one time. "He was in all points tempted like as we are, yet without sin." (Heb. 4:15) He alone was not guilty, which made Him worthy to be a sacrifice.
So, when Jesus died, He took upon Himself all of our guilt, shame, sin, and hell so that those who believe in Him would never have to face God's wrath. He died so that you could live. In this way, God's justice is fulfilled, the Law is satisfied, and mercy is made available to all!
The story of Easter can give us hope for two reasons. First of all, it tells us that we serve a living Savior. Jesus Christ is no longer in the grave -- He is risen! We don't have to merely look back on the writings of some dead man, we instead can serve the living King Jesus.
The second reason Easter can give us hope is that it demonstrates God's power to overcome death. When the tomb was found empty and Jesus appeared to His disciples (and many others) that first Easter centuries ago, God proved to the world that Jesus was who He said He was (Acts 17:30-31).
Jesus is the way to Heaven, the truth of God, the life we need. Easter is not merely a story of a man rising from the dead, it is a story of God's amazing power to rescue a hopeless and sinful race of human beings. Jesus died to set us free, and rose from the dead to offer us a new life with Him.
Why celebrate Easter? In short, without Easter, nothing else would really matter. Without the resurrection, what kind of life, and future, would we have?