Possible Clues:

• "Woot! The weekend is almost here!"
• Cry at the end of a workweek
• Worker's anticipatory cry
• Shout of relief
• End-of-the-wk. ''Yippee!''
• "Hyped for the weekend!"
• Crusoe's favorite letters?
• Weekly declaration
• Relieved letters
• "Time to unwind!" letters