Mint Chip Receipt is a tool that will link in to existing payment systems to provide customers with a receipt, stored on either the device itself, or online in a google documents spreadsheet. More options can easily be added to the standard as well, and since it's a completely open standard YAML specification, it is easy to edit by hand, not even requiring any software, and it's easy for software to read it, allowing any program to read and write it.
This specification will hopefully replace paper receipts, allowing users to track ALL their purchases (instead of throwing little paper receipts for a coffee and donut out) and keep track of where all their money goes. It is also friendly to the environment, as those millions of receipts are no longer printed and thrown out. It also allows the user to encrypt or sign/hash the receipt, allowing ultra secure proof of purchases, as well as encrypted receipts with state of the art public key encryption.
Even if I don't win the competition, I hope this gets implemented, because I, and everyone I talk to, would love to be able to plan our finances without doing any extra effort, keeping track of wasteful paper receipts, or entering purchases by hand, and estimating money spent.
The spreadsheet used in the video can be viewed at: https://docs.google.com/spreadsheet/ccc?key=0AoLIGftFk8GqdG9oZXk3akNzZlZDNkJ5SWcxcmxoX1E