EETimes covers a demonstration of plastic transistors from researchers at Princeton. The demo showed off working transistors made from organic conductors, semiconductors, and insulators printed onto an expensive polymer substrate. The initial goal is to produce a viable alternative to rare and expensive compounds used for the same purpose in organic solar cells.
In the past, attempts to print plasticized circuitry with an inkjet failed but not because of the materials. As the article notes, conductive polymers have been known for some time. The problem is that such polymers lose most of their ability to conduct when made soluble and hence printable. The researchers at Princeton developed a post-process that restores conductivity after printing.
Given that the transistor is the basic element from which computers are built, this should eventually have applications in computing where flexible devices would be useful. Couple this with an e-ink display and even the current ideas around embeddable computers could change significantly.