By Amy Ryan
December 01, 2006 at 12:00 PM EST

Another PopWatch HeadScratcher to get you through the weekend:

What do these five acts have in common?

The Four Seasons
Linkin Park
Willie Nelson

Your answer should be as specific as possible. Send your best guess to Be sure to write “HeadScratcher” in the subject line and include your first and last names in your e-mail. We’ll post the most interesting responses Monday afternoon.