Does H like kids magazines? DS loves them and 'reads' them over and over until eventually they start to fall apart or get torn then I chop all the good pics out and we do a session together (not whilst you are making dinner of course!) sticking them onto a shoe box to decorate it and they become his busy boxes.
He has several busy boxes full of junk (sorry, precious things) any bits I pick up form the £ shop, free toys off magazines, little characters, random pebbles and pine cones he's collected on trips out, random stuff from party bags, just lots of different things to rummage through. I also chop up the pictures off toy boxes (yk how they love the boxes!) and pop those in, he loves them even though he has the actual toy. Some toys come with a large leaflet type thing showing tons of other toys in the collection, he loves looking at those too so they go in.
We also have some other boxes, not junk stuff:
- coloured cotton reels (rolling, stacking, sorting, counting) and a drinking straw (threading, it's easier than a string)
- coloured drinking straws (posting through a cereal box, sorting, counting etc) and an egg box (stabbing/construction)
- various containers with different types of closures, usually these are tubs from hand cream, make up or herb jars, spread tubs, screw top bottles, flip tops etc all thoroughly washed out of course (all plastic)
- cookie cutters (we have all sorts, animals, letters, numbers, shapes...)
One thing I am keeping an eye out for is a pair of salad server tongs, DS likes to serve himself dinner with the metal tongs but I don't feel comfortable leaving him with them, one edge is shaped in a way that could hurt if he fell of it or something. So with plastic tongs I would set up two bowls, one full of something like dried pasta or stones and let him practice his scissor skills.
Like Buntybear said though, DS will watch a bit of TV and have his chill out time if he's been busy out and about. And like Shiv said I'd more likely switch the plans around so that he got some mummy or daddy time, we rarely do anything that DS can't get involved in, we leave it until he's in bed. He will clean the house with DP, vacuuming etc or I get him involved in making dinner or when DP isn't here DS will play kitchens in the kitchen with me whilst I cook.