If you're working in an Excel document that contains lots of dates and find yourself checking the calendar to see what day of the week each one falls on, there's a much easier way. A simple formula can save minutes, maybe even hours of your life you'd otherwise spend grabbing the datebook or clicking through the Windows taskbar calendar:

=TEXT(WEEKDAY(B2), "ddd")

In this formula, B2 is the cell containing the date (for example, 8/11/2010). This is particularly useful when creating schedules and such where you need to ensure key events land on work days. In my case, I use it to plan blog posts (among other things):

Use this formula to display days of the week

Don't be fooled by the "WEEKDAY" attribute - this function displays weekend days too!