Pretty simple, should do what it says in the title. When clicking the extensions button in the toolbar, there should be a button that allows you to temporarily disable an extension in the list. The main temporary disable options I'm interested in are being able to disable until firefox detects that the extension has been updated and then automatically re-enable it, or to disable it for the currently displayed website only. There could maybe also be one that lets the user select a discreet amount of time to disable an extension for. I think all of these would be useful for a number of users.