I have been trying to track down an audio file of this song, to no avail. There is a dead link (no pun intended) to a Greatful Dead setlist, which pleases me no end. I never knew they performed this, and one web page I came upon says they included it in no fewer than 50 concerts!
    I've heard it done very up-tempo, but also in a more gentle, quiet way, and am interested in comparing recorded versions.
    Can you please tell me where you know it from, and whom you've heard perform it?   Thanks in advance.   MMB (mmbryan@tampabay.rr.com).