Atanu Dey writes in an essay:

Compared to all other life forms in the known universe, our species can be characterized as the one that consciously solves problems. There appears to be – at least in some specimens of our kind – an inherent drive to not only solve problems but in fact to seek out new problems to be solved. Of course, some would argue that many of our attempts to solve problems in turn create new problems. That in itself is probably not such a bad thing because otherwise we would have little to occupy ourselves with. Confronting challenges – natural as well as artificially created – exercises our faculties and makes us feel alive and lends purpose and meaning to our existence.

I think that a simple taxonomy of problems would be useful. Type I class of problems are the ones that we are confronted with naturally and which we need to solve as a matter of practical importance. Examples of this class would be: how do we build a more efficient light source, how can we avoid global warming, how do we discover a vaccine, etc. In contrast to that, Type II problems are of no immediate practical importance and we ‘invent’ these problems for various reasons, primarily curiosity and the drive to comprehend the universe around us. To be sure, down the line, the results of Type II problems could have practical implications; but to begin with they are not motivated by a desire to change the world. Examples of this variety: is there is a largest prime number, why is the sky dark at night (Obler’s paradox), do neutrinos have a zero rest mass, etc.

Business Week writes:

LEGO Mindstorms NXT ($250) is a significant improvement on the original 1998 Mindstorms Robotics Invention System, and like its predecessor is a collaboration between the Danish toymaker and the MIT Media Lab. A more powerful computer brain lets the new robots run longer, more complex programs that incorporate inputs from up to four sensors. And using the rods and beams of LEGO Technic construction kits instead of the LEGO bricks of the original makes for more interesting designs. You hook the small, programmable computer, the NXT controller, up to sensors that can detect light, sound, touch, and, through ultrasound, the presence of nearby objects. The NXT uses those sensors to control up to three servo motors, whose output shafts can rotate in precise 45-degree increments.
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Sounds simple enough. But building robots requires manual dexterity and patience, a trait few children possess in abundance. Creating the suggested first project, a robotic vehicle that demonstrates all of the sensors, took me a good deal longer than the promised 30 minutes, even after I had sorted the myriad fiddly bits into plastic containers. LEGO recommends the kit for children as young as eight, but I suspect those younger than 12 will require a fair amount of adult help in assembling the models.