Lateral Thinking
Problem solving is traditionly done via Vertical Thinking: Conscious thinking in a selective, analytical, hierarchical approach. This is the traditional approach to problem solving.
Lateral Thinking is a manner of solving problems using an indirect and creative approach via reasoning that is not immediately obvious (thinking outside the box).
Lateral Thinking puzzules are used to train you to think differently.
Here are some links to Lateral Thinking Puzzles: