For you Rube Goldberg types, there are several games out there published by Sierra called The Incredible Machine: Contraptions, and The Incredible Machine: Even More Contraptions (TIM:EMC). For those too young to be familiar with Rube Goldberg, he drew cartoons depicting incredibly complex machines to perform simple tasks. TIM:EMC lets you build elaborate machines to do things such as catch mice (remember the old Mousetrap game?) using gears, pulleys, radio controlled explosives (no kidding) and the like. Very good at teaching logic, as well as cause and effect. The link to the demo is broken in the TIM:EMC page, but can be downloaded from the Sierra homepage under the downloads section.