By Amy Ryan
Updated April 14, 2007 at 04:29 AM EDT

Another PopWatch HeadScratcher to get you through the weekend:

What do these five acts have in common?

The Beatles
Johnny Cash
Cheap Trick
Joni Mitchell

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