The Novoflex Uniklem-26 is is a handy mini clamp solution for affixing a camera (with or without a ballhead) to akward scenarios such as tables, boards, pipes, car windows, etc.
Two support platforms are arranged at right angles to one another, and both have a 1/4"-20 thread.
Incredibly strong
Quick attachment/detachment from cameras/heads
Broad, rubber-based mounting platforms