Due to the success of the lateral puzzles in the "A riddle" thread, it seems appropriate to start a lateral thinking puzzle thread.
A rule of thumb to follow would be to allow those who do not know the answer to figure it out for themselves. If you happen to know the answer, please keep it to yourself and let the others have the fun.
Please feel free to start one at any point. It is not necessary to wait for one to finish before starting another one.