Draw a noughts and crosses grid on the board, and number each box from 1 to 9:

Now, divide the children into two teams, and label the teams "noughts" or "crosses". Each team has to answer a question correctly before they can place their symbol into an appropriate place on the board. The winning team is the one who gets a line of three of their symbols on the grid.

This can be used with any subject, e.g. maths questions.