Lighting 101 - Super Clamps
The favorite of most shooters is the "super clamp." It can latch onto just about anything, provided the thickness is a couple inches or less.
The bent arms of the clamping jaws make it particularly appropriate for clamping onto a variety of shapes. Pipes, railing, doors, shelves, tables, tree branches, electrical conduit running up the wall in a high school gym (not too tight...) are all no problem.
It comes with a stud that will accept a ball head or an umbrella stand adapter, too. So mounting your light is very easy. They are about $22.00, and every photographer should have at least one.
With the right accessory, they can hold remote cameras too -- or fix a roll of background paper to a light stand. A super clamp is one very useful piece of gear.
Next: Ball Bungees