I've been a fan of Strobist Speed Straps since I first read about them. I made a few of them and they seem to work at least as well as the sticky back velcro they replaced. (FWIW I've had good luck with WD-40, applied sparingly to a rag, to clean off the inevitable adhesive residue.)
The original style Speed Straps worked well but than I discovered an even cheaper and quicker 'no assembly required' solution that I'd like to share.
Sigma EF-500 DG Super for EOS sporting its simple speed strap.
First, instead of a bicycle inner tube, the friction enhancer is a couple wide rubber bands placed around the head of the flash. I prefer the blue ones that come from the supermarket and hold the stalks of broccoli together. (David Hobby probably doesn't eat broccoli but he's the master of light, I'm just a student.) Next up is the key to this super simple strap. Double sided velcro. Hooks on one side and loops on the other. The velcro is tightly wrapped over the rubber bands, overlapped at least a few inches, and cut to length.
While my simple strap may not be professional grade it has been more than adequate for the light enhancers I typically hang off my flashes.