Note: For the updated article, see How to: Modify the Ribbon in PWA in the Project 2010 SDK. The attached PWA_Ribbon_Customization.zip file includes the complete Visual Studio 2010 solution.
The attached PWA_Ribbon_Customization.zip file includes an article that shows how to develop and deploy a SharePoint feature that adds a Close Project button to the Project Details page in Project Web App. You can add a second feature to the same solution that removes, modifies, and disables several buttons and other controls on the Timesheet page, when timesheets are in the single entry mode. The code in the article is based on code samples by Adrian Jenkins and Maria Kouvlaki, Microsoft Corporation.