A popular way for companies to raise money for charity is to allow employees to pay a small fee to wear jeans to work. This demo app built on the Salesforce Platform provides a simple way for employees to sign up to wear jeans on a particular day so that program administrators know from whom to collect money. Note that this is not a production ready app at this point, it's intended as a demonstration of a simple app that can be built on Salesforce that all employees at a company might use, rather than something only for the sales or service teams.
Don't try to install this yet. A few things need to be fixed.