Need to repeat the same task in Office, like typing a block of text or deleting a lot of rows? You don't have to go burrowing through the menus -- simply use the F4 key to repeat your last action.
While this is an obvious tip for veteran users, it's worth reiterating for newbies, especially since the availability of any kind of 'redo' function is a tad less obvious in the Ribbon interface for Office 2007, compared to its relatively high visibility on the Edit menu in earlier versions. You can also use Control-Y for the same effect. Got your own favourite Office keyboard speeder (like using Control-Space to clear formatting? Share it in the comments?