This game is particularly good for younger children, but it also functions as a good demonstration of the concept for any age. Take three squares whose sides constitute the sides of a right triangle. Ask students to form a triangle with these squares. Many will be perplexed, but others may see how they can properly fit together at the corners to create a triangular space in between. If appropriate for the students in question, put the question to groups and add a time limit.
Once the children have the equation a^2 + b^2 = c^2 in front of them, they are ready to play a game of fill-in-the-blanks. You can begin with easy questions that give the side lengths as 3 and 4 and ask students to find the length of the remaining side by plugging in the numbers. The game becomes more difficult when you give them the hypotenuse and leave one of the sides blank. Finally, give students the length of the hypotenuse and ask them to determine how many whole number possibilities there are for the sides.
Draw appropriately sized squares that attach to the sides and hypotenuse of a right triangle. Divide these squares into smaller squares according to the lengths of their sides. For instance, a square with five-inch sides would have 25 smaller squares inside. Make distinctly colored stamps or blocks that fit in each square. One square could be blue, another red and the last yellow. Give the stamps or blocks to students in a jumbled pile and ask them to place them in the right squares.
Use the Jeopardy format to give answers about the Pythagorean theorem and task students with determining the correct question. An example of such an answer might be "the sum of the squares of both sides." The question might have been "What is equal to the square of the hypotenuse?" For added fun, put volunteer students in front of the class in a scenario that resembles the real TV show.