E.M.D. (Eat My Dust) is, for my money, David Grisman’s most paradigm-shattering tune, and made its first appearance on the 1976 David Grisman Quintet record. The mandolin parts are wonderful, but Tony Rice’s guitar break
(this one)
forever changed my conception of what the guitar could be made to do. There are several versions of the tune out there in YouTube land, each demonstrating different facets of the tune and showcasing the approaches of virtuoso players:

Grisman Quartet, early 1980s I think. Tony’s break: 1:10-1:45

Bluegrass All-Stars, with Alison Krauss. Tony’s break: 2:40-3:20 (good sound but jerky video)

Tim May and David Harvey, the tune starting after 3:30