Doug Sahm, Jerry Garcia and Leon Russell, Thanksgiving Jam, 1972
I got this from Austin based songwriter Joe Pug, who posted it on his facebook page. It's a concert from the Armadillo World Headquarters on Thanksgiving weekend, 1972, featuring Doug Sahm, Jerry Garcia and Leon Russell tearing into some country, rock and blues songs, backed up by members of some Austin bands of the day. They cover everything from Hank Williams to George Jones to TBone Walker to Bob Dylan. It has a similar Vibe to Doug Sahm's masterwork, Doug Sahm and Band, from the same period.
To listen to it you have to download a zip file. The download is free, but you might have to purchase a program to open it. I didn't, though. My Mac opened it automatically, with no problems, and played it through I Tunes. It's an awesome album, man. About 90 minutes worth.
Here's a link to the blog that tells the story, gives a complete track listing and has a link to the free download: