Every year, the leftover amount on unused Metrocards can total $52 million. Students at NYU's Interactive Communications Program have designed Metrochange, a cool way to make sure all that loose change gets put to good use. A kiosk, equipped with Ardunio, an ethernet shield, a transmitter and a receiver, will tell you how much money is left on that piece of plastic that's probably somewhere at the bottom of your purse. You push a button to donate the money into a central fund which will then go to charity. The old Metrocard will then be recycled. The students are currently looking for partners on the project. Read about it on the blog.