Bruchko by Bruce Olson is my favorite book, besides the Word of God.
I don't believe an honest atheist could read this book without undergoing serious introspection.
This is the best evangelizing tool I can think of, particularly for young people. Just hand your kids a copy.
http://www.bruceolson.com/
http://www.bruceolson.com/english/english.htm
http://www.christianbook.com/Christian/Books/product?item_no=59939&item_code=WW&netp_id=446843&event=ESRCN&view=covers