My boys love to play with their iPad. My oldest who is 4 ½ spends an average of about 45 minutes each day playing a variety of games. Some like Endless Alphabet are educational while others like Fruit Ninja, are not so much.
One constant that we can always count on, regardless of cultural or social situations, is that young children will play. If you ask a young child why he plays, he'll probably say "Because it's fun!" Of course, being adults, we have to define play in terms we are comfortable with. Below is an overview of play theory and theorists from the past 100 years.