What's your favorite tech idea of the year?

Last week I commented on the New York Times Magazine’s “9th Annual Year in Ideas.” Here are some tech ideas worth a look:

–The Advertisement that Watches You.  Billboard advertisements use cameras and face-tracking software to serve up gender-appropriate or otherwise context-sensitive ads. Sixt, for example, presents different pictures of rental cars to men and women.

–Printable Batteries. Fraunhofer Research Institution for Electronic Nano Systems has demonstrated a 0.6-mm-thick battery that can power equally thin sensors or blinking magazine covers.

–Waste Tracking. Valerie Thomas, a professor of industrial engineering and public policy at Georgia Tech, is developing what she calls the Smart Trash system, which employs barcode scanning at the trashcan. A smart trashcan can then, via Wi-Fi, alert trash collectors to the possible salvage value of disposed goods.

Sound Cannon. The Long-Range Acoustic Device (LRAD) can deliver sound at up to 152 decibels. Critics call LRAD a weapon; its manufacturer, American Technology Corp., calls it a “communication device.”

Guilty Robots. Roboticist Ronald Arkin of Georgia Tech has designed prototype software for ethical robots for the US Army. The software includes algorithms that model guilt, the goal of which is to help battlefield robots minimize collateral damage. That’s hardly in keeping with Asimov’s First Law of Robotics, but maybe it’s better than nothing.

Weapons of Mosquito Destruction. Szabolcs Marka, a Columbia University astrophysicist, received a grant the Bill and Melinda Gates Foundation to develop a of futuristic mosquito net that employs a “light shield” through which mosquitoes will not fly.

Which idea is your favorite? Is there a tech idea the Times missed?