No really, these earphones vibrate in synchronization with the beat of the music you're listening to.
I don't know about you, but these are the inner-ear type. Personally, I hate anything being in my ear. I think that something in there vibrating wouldn't be any better.
Still, I'd at least like to give this a shot to see what they feel like.
More information and pictures inside.

AudioTechnica Corporation will release the "ATH-CV5" series of earphones o­n March 10th. The earphones vibrate along with the beat. They are officially Open Price, but indicators suggest the cost to be around 3,000 yen.

The earphones include a "vibration unit" inside the earphones themselves, that synchronizes vibration with the beat of music - therefore external power is not needed. They use a 13.5mm Neosium Magnet driver unit.

Five body colors are available: LG (Lime Green), OR (Orange), RD (Red), SV (Silver), and WH (White). The response frequency is 20Hz - 20kHz, and the maximum output pressure is 100dB/mW, with a maximum output of 30mW. Impedence is at 16 ohms, there is a 50cm cord, and the plug is a gold plated stereo mini plug.



Inspired by:
http://www.watch.impress.co.jp/av/docs/20040304/autech.htm

Product Information:
http://www.audio-technica.co.jp/products/hp/ath-cv5.html