The NXT NXT challenge is the latest building challenge from LEGO! Your model has to incorperate two NXTs, but only one has to be built into your creation, so the other one can be used as a remote control, etc. The NXT bricks HAVE TO communicate with each other though, so some knoledge on how to program a NXT brick to communicate via Bluetooth may be useful. All participating models have to be uploaded complete with write-up, .RBT file, LDD file(!), pictures and the Tag "NXT200805" by Monday the 30th June, 2008.
Making an LDD file with LEGO Digital Designer is a rather off putting thought though, as that element of the submission will probably take the longest time to complete (After the physical model of course!)
Here's a link to the Official LEGO website for this challenge: