If two balloons are rubbed on a wool sweater they should stick to each other?

The balloon has a greater affinity for electrons so it obtains a negative charge after being rubbed against the sweater. The balloon, containing a highly negative charge, sticks to the wall because it is attracted to the positive charges in the wall (opposites attract). After a while, the balloon's extra electrons move to the wall and both objects become neutrally charged. Lacking any significant attraction, the balloon will fall off the wall.