How to play with your children

You'd think after 4 children I'd know how to do this, but I don't.  My 3rd child seems to want me to play with him more than the others did, and frankly, I don't know how to. Which is why I am avoiding it by a little bit of cleaning on the side, or making excuses and writing emails or, ahem, blogs.  When I have no more excuses I do actually settle into the task, but am often distracted and find myself  offering him tv.  Which normally I am nagging him to turn off.  Why is it so hard, surely as a child I longed for it.  Now I hate it, its really quite boring and I can only maintain it for about 3 minutes.  I saw one mum set herself the task of 30 minutes playing with her child a day. And certainly Dr Tanya Byron recommends it above all else.