LED Throwies are an inexpensive way to add color to any ferromagnetic surface in your neighborhood. A Throwie consists of a lithium battery, a 10mm diffused LED and a rare-earth magnet taped together. Throw it up high and in quantity to impress your friends, city officials(!), express your creativity or your own special message!

LED Throwies are an open source graffiti technology developed at the Graffiti Research Lab, a division of the Eyebeam OpenLab.

Click here for instructions on how to make your own Throwies (and loads of other useful,.. or not so, but still interesting things).