I was at this show this past year:
http://www.archive.org/details/um2011-07-15
Check out The Triple Wide, it's pretty typical of their songs. They usually have a long long buildup but they get dirty and jam it out once they get into the groove. Not really their best show ever because they had a short time slot because Further (remaining members of the Grateful Dead) took an extra hour to come on stage which ate into Umphreys timeslot, but you can find hundreds of other shows by them on this site.
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this.
what the **** is a Barack?! - DMX