These pixel drink coasters are made of paper and come in 50-unit packages for $8. Nothing special there until you notice that they have different shapes, which are not actually made at the factory: The coasters come in a single sheet, folded in 50 segments that you can cut in any way you want using the one-centimeter-long square perforations that divide each segment into 110 pixels. The results are beautiful, including an obligatory Space Invaders theme.
According to Technabob, the paper is special, which allows to resist the condensation and even get reused. [25togo via Technabob]