Conversation so far:
what is vortex I?
McCall decided to hold a rock festival at Milo McIver State Park near Estacada, Oregon called Vortex I: A Biodegradable Festival of Life,“
was vortex I popular?
The festival, nicknamed The Governor's Pot Party by Oregonians, was a success, attracting between 50,000 and 100,000 people
were there problems having Vortex I commence?
I think I just committed political suicide, McCall is reportedly remarked immediately after approving Vortex. Vortex was the first and so far only state-sponsored rock festival in U.S. history.
who led Vortex I?
Koinonia House, a peace-activist Christian group hosted a public meeting and from there the idea of a Biodegradable Festival of Life called Vortex 1 came into being.

Question: who played at the festivle?
Self-contained rewrite: who played at Vortex I?