I wanted to put a quick post in here about an application I have built on the Force.com platform. It is a micro-grant site built on the Force.com platform that leverages the PayPal adaptive APIs. Currently a finalist in the PayPal developer challenge. Here is a write up Salesforce.com did about it:
http://blog.sforce.com/sforce/2010/03/a-microgrant-solution-built-on-forcecom-.html
Link to applicaiton:
http://www.grantachance.com