Under the Overpass by Mike Yankoski
What do you do when you see a homeless person? Most people "politely" ignore them. But college boys Mike and Sam decide to do more than just fell sorry for them, they become them.
For five months, the boys choose to go homeless in five different cities across the country. They give up most of their possessions and leave their families, friends and school to go experience a new life. This is an amazing story of faith and redemption.