I became a Christian around March 1998, when it became obvious to me that I couldn't avoid the fact that the Bible was an accurate historical record of an amazing series of events, and that a serious and lasting response was demanded.
What Christians Believe
This is a summary of the key beliefs of the Christian faith, as set out in the Bible. There is a mass of compelling evidence to show that the Bible is an accurate historical document, which points to and records the life of Jesus Christ, the Son of God.
In the beginning, God created the world and all that was in it from nothing. He created Man to live in the world, in a perfect relationship with him. However, Man decided that he didn't want God to rule his life, and so rebelled against God. For this, he was cast out of Paradise (this event is known as the Fall). Ever since, we have not been able to live up to God's perfect standards, and so when they die each person is destined to be judged by God and (rightly) experience God's eternal punishment.
However, because God is loving and cares about His people, he sent his Son, Jesus, to earth to live a perfect life, thereby becoming the only person ever who would not be found guilty when judged. This made him uniquely qualified to take the punishment for all our wrongdoing upon himself, and so when he was crucified, he suffered and died in our place as our substitute and representative. But after three days, He rose from the dead and later ascended to Heaven, from where, today, he rules the entire world.
So, what this means for you, me and everyone else on the planet is that we can never live up to God's perfect standards - we will always fall short of them. Being "a good person" is not enough - because "good" is not the same as "perfect". So the only way to meet God's standards, get to Heaven, and avoid Hell, is to trust in Jesus, accepting him as Lord in your life, and believe that he died to save you from the judgement you deserve.
"For God so loved the world, that he gave his One and Only Son, that whoever believes in him may not perish, but have eternal life." - The Bible, the Gospel of John, chapter 3, verse 16.