And they are sweet!
Screen printing is a unique medium. There are a number of restrictions that make designing for screen printing a unique challenge. The guys from Aesthetic Apparatus understand this very well and their designs utilize the strengths of the medium to amazing effect.
They get a lot out of only a couple colours by the way they layer parts of the images and use the natural transparency of the inks to their advantage.
You can see more of their work here:
And if you are want to see a fun video of them printing a sweet poster for the movie "The Shining" check this out!