When Spike Lee's Mars Blackmon said "It's gotta be the shoes" I don't think he had this in mind:

Last month, the German athletic-gear company adidas unveiled its "1," a battery-powered running shoe equipped with digital sensors and a mini-motor that automatically adapts the tension in the sole to a runner's pace.

VectraSense Technologies in Massachusetts followed on adidas' heels. It's touting a new all-purpose shoe that uses a computer chip to sense pressure on the sole and adjust the air pressure in chambers embedded in the toe and heel.

Hi-tech shoes may be more than just hi-tech faddishness. They might help old people stay upright:

In Providence, R.I., Afferent Corp. is developing vibrating shoe inserts to keep elderly walkers from falling. They're based on research by a Boston doctor, who showed that tiny, imperceptible vibrations on the bottoms of feet could stimulate elderly people's worn-down nerve endings and trigger natural balancing responses.

That's pretty cool. There's another group at MIT working in conjunction with other firms trying to create shoes that will generate energy for military applications:

Paradiso's team also devised a shoe that could generate a few milliwatts of electricity with each footfall. A California lab is taking the concept a step farther: It aims to market to the military a shoe that can power night-vision goggles, walkie-talkies or a global positioning system.

BTW: the Adidas shoes will retail for $250. The VectraSense shoes will retail for $450.