ZEM headphones are a new product created by an audio researcher, who claims to have come up with a noise cancellation technique that doesn’t require specialized electronics in order to work. This makes the headphones lighter and cheaper, but sometimes products like this oversell and under deliver.
The headphones are light, weighing in at a mere 2oz, fold up, and look somewhat less then fashionable. The headphones will run you about $90, so it might be worth it to pick up a pair and try them out. I’m somewhat skeptical myself, but technology does move forward, so it could be possible that they work. You can order them online, directly from SensGard.