I don't know if you have heard of Scott Mason or not, but he has an AMAZING testimony. It's a testimony of grace and forgiveness. He has been compared to Paul, as the worst of sinners now doing great work for Christ.
Scott is a Christian speaker and author. It amazes me that schools actually pay him to come and speak about the transformation that Christ did in him. I think what's even more amazing than secular schools inviting him to speak about Christ is that prisons actually give him (an ex-convict) freedom to move about unrestricted. I recently got to hear his testimony and it is so powerful. If the world can see the change in him and grant him forgiveness and grace, it saddens me to think that we as Christians, wouldn't offer that same forgiveness to him or others like him.
You can read part of Scott's testimony here. But that really hardly does it justice. The audio version that I listened to was over an hour long and still just scratched the surface. I strongly encourage you to purchase his book "No Reason to Live". All of the proceeds that he gets from book sales and speaking engagements go to help his prison ministry. He and his wife and children have opened up a rehabilitation house for women who have recently been released from prison. It is their hope that someday these houses will cover the nation, not just for women, but for all convicts so that they can be shown the love of Christ, and given a chance to turn their lives around.