On Friday when the boss shouted us pizza, we had a problem with everybody trying to order various pizza's, various half pizza's, and various sized pizzas over email. Then the orderer had to collate all of these into a coherent order for the pizza shop.
In the end, we wrote a new module for our internal project management system called "The Pizza Module".
The Pizza Module would be pre-populated with the menu of our favourite pizza shop, so that you couldn't place an order for something that didn't exist. It would then allow people to enter orders via intranet, and then resolve things like four people ordering "half a mexicana" into two mexicana's. It also came with the "fat graph" report, which always had the orderer with the fattest amount (due to people who didn't have access to the intranet ordering through him).
Finally, it was fitted with a feature that prevented ordering, unless your timesheet was complete for the past two months. For a long time, it was very successful, and worked perfectly as intended).
However, in the end, it broke down when we moved away from it as we shifted to a different project management system. Nobody could be bothered writing a new pizza module (or refactoring the old pizza module to work with various project management systems), so we now use a collaborative Google doc with a table that people can place orders in. This is a Bad Idea™, and is far more open to gaming than the system described in the article. However, it is good for 5 minutes of entertainment on a Friday morning, watching people going back and forth on the shared doc.