The Atlantic Wire's Allie Jones writes:

If you've read every Shakespeare play from King Lear to All's Well That Ends Well and are dying to get your hands on some more Bard, you're in luck. New evidence suggests that Shakespeare helped out Thomas Kyd with the play The Spanish Tragedy, a revenge tragedy from the late 16th century that is believed to have served as the basis for Hamlet.

You can download a free copy of The Spanish Tragedy at Project Gutenberg and decide for yourself if you detect a whiff of Shakespeare in it.