Ms 4yo DS is a bit the same. I usually end up helping (if it's a bit job, I don't really mind). But, his favourite thing to play with/on at the moment is DH's xbox. The threat of not being able to play on that for a day (or two or a week, whatever I decide) is usually enough to sort him out. Does your DS have something (even just one thing) that he would hate to have taken away? What about TV?