My berlin-based friends Josh and Vivien own this brilliant italian invention called Dosacaffe:
The dosage-maker controls easily the perfect amount of ground coffee that is needed in order to produce a great coffee. It’s metallic ring can be attached to all standard coffee makers. The Dosacaffe dosage-maker is attached on the opened coffee container and the perfect amount of coffee is controlled by one full spin on the container’s handle.
I just *finally* found a place where you can order them online. Here.