Xbox 360 Kinect and boxed Kinect Adventures Game
Bought it without realising it only had the plug for the slim. (They don't tell you these things!)
Rather than paying £50 (at the time) for the psu adapter, I converted the cable so it would work in my fat xbox, which it does just fine (and can be seen working). The original end is included, just not connected.
It does come with a box, but the box is in the loft, so can get it if you really want it.
£35 (Note the cheap ones do not come with the adapter)