1. A plan to completely scrap a project after making significant progress and start over from scratch. Some parts of the original plan may be salvageable but most well have to be completely reworked for the new longhorn plan.
2. A reference to the scrapping of Windows Longhorn after three and a half years of development.
Guy 1: Hey you know that project you've been working on since you started with the company?
Guy 2: Uhhh, Yeah...
Guy 1: None of it's working and the business requirements have changed.
Guy2: I'll get started on the Longhorn Plan