As is tradition, The Mohawk - a dive bar across the street from Mass MoCA in North Adams, is serving as the home of the Bang on a Can Summer Marathon afterparty. But even after last year's wild scene, I have to do a double take when I see Terry Riley sit at the bar with his wife and order a pair of Sammies. Even more bizarre: they sit across from me at one of the long tables, and we start talking about his organ concert at Disney Hall earlier this year, during which he dubbed the 6,200 pipe organ "Hurricane Mama." (He is currently in talks with Disney Hall to secure rights to the recordings for commercial release.) I tell him about the Messiaen concert I heard at La Trinite in May; he tells me that when he lived in Paris, he worked as a paper boy, and had Trinite on his route.