Some nice lateral thinking exercises.....
Please try them when you have time (at home with kids ...)
    1. There is a man who lives on the top floor of a very tall
    building. Everyday he gets the elevator down to the ground floor
    to leave the building to go to work.
    Upon returning from work though, he can only travel half way up in
    the lift and has to walk the rest of the way unless it's raining!
    (This is probably the best known and most celebrated of all
    lateral thinking puzzles. It is a true classic. Although there are
    many possible solutions which fit the initial conditions, only the
    canonical answer is truly satisfying. )
    2. A man and his son are in a car accident. The father dies on the
    scene, but the child is rushed to the hospital. When he arrives
    the surgeon says, "I can't operate on this boy, he is my son! "
    How can this be?
    3. A man is wearing black. Black shoes, socks, trousers, lumper,
    gloves and balaclava. He is walking down a black street with all
    the street lamps off. A black car is coming towards him with its
    light off but somehow manages to stop in time.
    How did the driver see the man?
    4. Why is it better to have round manhole covers than square
    This is logical rather than lateral, but it is a good puzzle that
    can be solved by lateral thinking techniques. It is supposedly
    used by a very well-known software company as an interview
    question for prospective employees.
    5. A man went to a party and drank some of the punch. He then left
    early. Everyone else at the party who drank the punch subsequently
    died of poisoning. Why did the man not die?
    6. A man walks into a bar and asks the barman for a glass of
    water. The barman pulls out a gun and points it at the man. The
    man says 'Thank you' and walks out.
    (This puzzle claims to be the best of the genre. It is simple in
    its statement, absolutely baffling and yet with a completely
    satisfying solution. Most people struggle very hard to solve this
    one yet they like the answer when they hear it or have the
    satisfaction of figuring it out. )
    Scroll down for the solutions. 
    1. The man is very, very short and can only reach halfway up the
    elevator buttons. However,if it is raining then he will have his
    umbrella with him and can press the higher buttons with it.
    2. The surgeon was his mother.
    3. It was day time.
    4. A square manhole cover can be turned and dropped down the
    diagonal of the manhole. A round manhole cannot be dropped down
    the manhole. So for safety and practicality, all manhole covers
    should be round.
    5. The poison in the punch came from the ice cubes. When the man
    Drank the punch, the ice was fully frozen. Gradually it melted,
    poisoning the punch.
    6. The man had hiccups. The barman recognized this from his speech
    and drew the gun in order to give him a shock. It worked and cured
    the hiccups-so the man no longer needed the water.