The free electronic gizmos that are starting to appear more often with products like breakfast cereals are actually quite complex little beasties.
Brian Dipert's blog on EDN has this post - See inside a cereal surprise: Dissecting the Xbox Mini electronic games - which breaks down some free toys from Frosties packets.
Brian goes into exquisite detail in his breakdown of these free toys, with the conclusion that they pack in a lot of engineering ingenuity. He asks:
How do you make an electronic toy inexpensive enough that it can be given away within a box of Froot Loops while still retaining enough compelling features to motivate a cereal purchase?
Read Brian's post and be amazed at how these hand-assembled toys do their stuff.