Reader gkrieshok likes the idea of binder clips as cable catchers, but not having to fish wires through the handles when you need to pull the cables away. His solution uses strong magnets taped to the clips to keep cables under control.
Before you jump into the comments, you should know that, yes, gkrieshok is using very strong magnets, possibly obtained from the inside of another hard drive, and that's the kind that can wipe a hard drive if applied directly. But gkrieshok is electrical-taping these magnets to binder clips that are then attached to the side of a desk, and his Macbook will, presumably, never be vertically passed down the side of his desk. As some have suggested, it takes both proximity and intent to really do damage to your data with incidental magnet exposure.
So if yours is a setup where you've got cables you occasionally need to grab on a side of a desk, a decent bit away from your laptop — or, better still, a few feet from a desktop — consider gkrieshok's technique. If you're concerned about exposing spare hard drives or working computers to magnets, just admire the bravery of this setup.