Update: Shaun has some picks of his own.
Time's a wastin' and this is how I'm wasting it today. Discovered
YouTube, like Flickr but for sharing video. A search for Bob Dylan brings up much goodness.

The excellent video for Jokerman.
Watch Bruce Springsteen and Eric Clapton manfully try to sing harmony with him.
Several duets with Johnny Cash, including a relaxed One Too
Many Mornings. Then watch Bobby do Train of Love at the
Johnny Cash tribute in 1999. People can upload personal vids too,
like this five year old recreating the Subterranean Homesick
Blues film.
A few others I've been watching:
A 14yo old Hank Jr on Ed Sullivan.
Hank Snr with Anita Carter, intro'd by June
Cash goes Celtic, 40 Shades of Green
Son House -- Death Letter Blues
Flying Burrito Bros -- Older Guys The boys go wacky on a boat
This is great. Johnny Cash and Emmylou Harris. Marty Stuart on
mandolin, his jacket compliments his mullet perfectly.
Aretha -- I Never Loved A Man The Way I Love You
Waylon and Willie -- Good Hearted Woman Is that Emmylou there too? Up the back with the bad perm?
Lucinda Williams -- World Without Tears
Gillian Welch and David Rawlings
R.E.M. & Bruce Springsteen - Man on the Moon
Earl Scruggs with Dylan