In 1969 three musicians met in a room in Houston Texas to see if there was any chemistry to form a band. They jammed an inprovisational music style called Shuffle In C. With no rehearsal, they played a single song for 45 minutes straight with each of them wandering around musically and taking turns soloing while the other two member played supporting notes.
At the end they agreed "I think we've got something here.' They became That Little Ole Band From Texas known as ZZ Top. Here is their song La Grange that picks up where that first session left off. RIP the drummer Frank Beard.