Few people are likely to have access to lots of discarded inner tubes from old bicycle tires. In case you do, these IT Clips offer up a way to let you recycle them into useful tie-down straps.
Styled like a plastic buckle, you wind the tubes around the inner portion of the clip, turning them into functional bungee straps with a convenient latching mechanism. Of course, you can always just tie the tubes into a knot after wrapping it around a box, but good luck clearing up that knot (I've actually tried that -- not fun).
The current version of the IT Clip can work with mountain bike tubes between 1.5 to 2.5 inches in width. Securing the two ends is accomplished with a simple hooking mechanism, which lets you latch and unlatch with a single motion. It comes in four colors -- red, green, yellow and blue -- which should help alleviate the insufferable unsightliness of the inner tubes it's attached to.
In case you need to extend the length of the cord without having to redo one of the ends, they're also selling IT Hooks, which are hanger-like wires you can slip around each clip. They appear to be peddling them to tire manufacturers as giveaways, although, they could make for decent impulse buys at a local bike shop.
The IT Clips are available for $5 each.