I did not know that “almost every star is a binary star.” Remarkable. So is this: Mizar (“my czar”) – the middle star of the Big Dipper’s handle – is actually four stars (a binary system comprised of two binary systems.) Check out the spectroscopic image.
The colors seen here show periodic doppler shifts, indicating that both stars are themselves binary systems.
I give this factoid 4 (out of a possible 4) stars.