MCP Philo, well known for a lot of exciting robots, deep insight into the NXT internal electronics and as author of many LDraw parts and of a NXT book (just to name a few things), has published a new fascinating device: a NXT-based 3D scanner.
It scans small objects using a needle mounted on a LEGO® linear actuator and reports the data to a computer where they can be used to generate a related 3D CAD model:
Intriguing!
Note that the scanner has been programmed with pbLua, the NXT programming language based on Lua.
A lot of more information can be found on the associated web page.