make playdough and play with it (in the kitchen!!)
Arna and I played with Playdough yesterday and she trampled it into the lounge while I was on the phone (people ring at the worst times!)
Maybe do the same with paint? (ok I am suggesting messy stuff!!)
I have 3 nursery rhyme cd's that I have put on once a week for Arna and we just sing those - that lasts about half an hour before she gets bored! (You can borrow them if you want)
Do a scatter toys morning / afternoon - get all his toys out of the toy box and let him go wild!
Not really sure of anything else... Hope this gives you some ideas