Here is a list of all shortcuts using the Windows logo key on your keyboard ( ), courtesy of Tech Republic. They did a pretty good job with this by listing all of them, not just the common ones. Note that some of them work only in Windows 7.
Between the Sheets — Excel podcast episode 31: Excel’s secret DATEDIF function
A quick and simple way of finding the number of days, months or years between two dates is Excel’s secret DATEDIF function. When you type it in a worksheet, there’s no popup syntax help to indicate the function exists.