With Mindstorms NXT 2.0, you can build and program your own personal robot. The package contains a decent selection of Lego Technics parts, plus a central computer unit (the NXT "brick") and a range of sensors and motors.
It also comes with instructions for building a range of suggested projects, such as the ShooterBot, the Colour Sorter and the RoboGator. But, this being Lego, there's limitless scope to modify and expand upon the standard models.
Visit the Mindstorms website and you'll find a wealth of tips and additional blueprints.
You can make your robot perform basic actions using the four buttons on the front of the NXT computer unit, but that barely scratches the surface of Mindstorms' potential.
The bundled CD contains a child-friendly drag-and-drop program builder for Windows and Mac OS X that can produce sophisticated routines using loops and logical tests.
And more advanced programmers can use the free SDK to craft NXT programs in their language of choice - or natively within Microsoft Robotics Developer Studio.
True geeks can freely customise the open-source firmware, enabling their creations to take on capabilities even designers of Mindstorms never envisaged.
Once your program is complete, simply upload it to the NXT (via USB or Bluetooth) and your software can control its three servo motors and respond to input from four sensors.
These have been slightly modified from the original NXT package: you now get two touch sensors, a colour reader, and an ultrasonic sensor that can identify proximity and movement. The NXT 2.0 brick can also play sounds and display images or messages on its screen.
Your robot can be extended with additional Lego Technics parts too, but there's no official way to access more than three motors and four sensors, placing a disappointing limit on what you can achieve out of the box.
If you're feeling ambitious, you can invest in third-party expansion modules which support more motors and extra sensors, such as a camera, a clock and a compass.
It adds up to a hugely flexible package that, with a little ingenuity, can be made to perform more or less any function imaginable.
It isn't cheap, and if you have big plans you'll need to budget for additional parts on top of the base price. But as a flexible, fun introduction to robotics, there's nothing to rival Lego Mindstorms NXT 2.0