Doc, re Grits and Groceries schedule: It's complicated. That's why I included the website.
On shows: back in the day: the last Cream concert, late Janis Joplin, Pink Floyd test-driving Dark Side before the album, Hendrix doing the Star Spangled. The best: The Who doing Tommy and the live at Leeds stuff in ATL, The Who doing Who's Next and then tearing everything up in Rome in 72. Grateful Dead 1968-1988.
In the modern era: Too many amazing shows at Bonnaroo 2002-2011. Phish, Primus, Moe, Jack White, various jams, too many wonders to relate.