This song has been covered by many greats, and by many not-so-greats. Witness the album 'The Transformed Man', featuring singing and spoken word by the acclaimed actor, William Shatner.

The cover of Mr. Tambourine Man on that album is quite possibly the most horrifying recording made ever, barring maybe Leonard Nimoy's cover of CCR's 'Proud Mary'. It's worth listening to the whole song just for the inhuman scream at the end.