Blimey, I am rubbish at the whole playing business. DS1 asked me yesterday if I would play with him, he said I hadn't played with him for ages.
In my defence I put my efforts into doing things together, walking and talking, swimming, going to the park, going for bike rides, trips to coffee shops , reading together, shopping (getting the kids involved though, you hold this, what cereal should we get, what do you think of these jeans etc, etc), making cakes/biscuits, tidying the house and gardening. DH is much the same, he gets them involved in DIY projects and tells them all about coffee making, although he probably scores higher when it comes to actual playing.
I just really struggle with the down on the floor zooming cars about etc. I do try to help with jigsaws, following the diagrams for lego/knex and at a push playdough.
I really do feel bad about this though.