Having played a lot of music, and following a chance recruitment as a Bollywood extra in Goa, I have a relatively low Erdös-Bacon-Sabbath number. This is a geeky and completely useless index that combines three metrics of connectivity to the mathematician Paul Erdös, to the actor Kevin Bacon, and to the band Black Sabbath.
Combined Erdös-Bacon-Sabbath number: 9
Erdös number: 4
I coauthored Conceptual Models of the Wind-Driven and Thermohaline Circulation with Henk Dijkstra;
Henk Dijkstra coauthored The Dynamics of a Low-Order Model for the Atlantic Multidecadal Oscillation with Henk Broer;
Henk Broer coauthored Preface [Special issue in memoriam J. G. van der Corput (1890–1975)] with Robert Tijdeman;
Robert Tijdeman coauthored Some Diophantine Equations with Many Solutions with Paul Erdös.
There are a few alternative routes via Henk Dijkstra, Jonas Nycander and Lawrence Mysak.
Bacon number: 3
I appeared as an extra in Agneepath, starring Amitabh Bachchan;
Amitabh Bachchan appeared in The Great Gatsby with Joel Edgerton;
Joel Edgerton appeared in Black Mass with Kevin Bacon.
Sabbath number: 2
I played in various jazz performances with Digby Fairweather during his regular visits to the Lady Mary High School, Cardiff in the early-mid 1980s;
Digby Fairweather played as a member of The Secret Police alongside Neil Murray, a member of Black Sabbath.