Here are links to a few videos of note:

Weir and Garcia visit Letterman in 1987

Phil Lesh, Les Claypool, Mike Gordon, Gabby La La and the Benevento/Russo Duo at the Jammys

Our New Groove of the Month, Scarecrow Collection, acoustic

Jefferson Airplane, circa 1970

Chris Harford, Scott Metzger, Joe Russo, and Dean Ween at the Freaks Ball 2007

The Disco Biscuits, "Crickets" High Sierra Music Festival- 7/6/03

Phil and Friends, "Help on the Way"- 5/19/06

David Bowie and the Arcade Fire, "Wake Up"

"Tube" on YouTube- Phish, 8/13/96