Spreadsheet Fu for Week day (text) for a given date

Use the following formula to get the day of the week (e.g. Friday) for the given date field:

=TEXT(WEEKDAY(A1), "DDDD")

The WEEKDAY function returns the day of the week as a number (1-7) and the TEXT function formats that number into the corresponding text value for that day of the week e.g. 1=Sunday…7=Saturday.