Mason Wartman quit his Wall Street job to open a pizza shop in Philadelphia that does more than serve delicious cheesy bread. Each slice is only a dollar-and Wartman encourages all his patrons to "pay it forward" by giving another dollar so a homeless person can eat for free...
This system is kept in order via sticky notes on the "pay it forward" wall. If a person cannot offered their meal, they simply take a post it from the wall and get a slice of pizza for free.
Rosa's serves around 40 homeless people a day.
And gets cool love letters like this regularly.
What an awesome business.