Bisection search game
Some things I think would improve your code, which is quite correct:


Having variables for high and low, you shouldn't hard code their values in the opening print.
You should use // to make sure you are getting integer division.
You can write guess = (low + high) // 2 only once, if you place it as the first line inside the while loop.
When checking for pointer, you may want to first convert it to lower case, to make sure both h and H are understood.
Make your code conform to PEP8 on things like maximum line length.
Using the format method of str can make more clear what you are printing.


Putting it all together:

high, low = 100, 0

print('Please think of a number between {0} and {1}!'.format(low, high))

guessing = True
while guessing:
    guess = (low + high) // 2
    print('Is your secret number {0}?'.format(guess))
    pointer = raw_input("Enter 'h' to indicate the guess is too high. "
                        "Enter 'l' to indicate the guess is too low. "
                        "Enter 'c' to indicate I guessed correctly.").lower()
    if pointer == 'h' :
        high = guess
    elif pointer == 'l' :
        low = guess
    elif pointer == 'c':
        guessing = False
    else:
        print('Sorry, I did not understand your input.')

print('Game over. Your secret number was {0}.'.format(guess))