HiTechnic released their ‘Prototype board’. The Prototype board is available in two models, one with a prototype grid to solder your designs creating a permanent sensor or device interface and the solderless design that plugs into a solderless breadboard so you can quickly create many designs and reuse your electronic components. They also have a Prototype Kit which includes jumper wires and a breadboard.

What can you do with this? Well, even without exensive knowledge in electronics you can build your own sensors for NXT. The board has 5 analog inputs (i.e. the NXT will read a numeric value proportional to the voltage on these pins) and 6 digital pins which may be inputs (e.g. switchs) or outputs (e.g. LEDs). Also, you have 9v, 4.3v, 5v and 3.3v power supply wires.

Take a look at HiTechnic website for more details.