So here it is. My only rule.
Always let the kids come to you. Try not to clap your hands and say “OK kids we are going to do this activity now.” Even in your best ‘Meryl Streep THIS IS GOING TO BE AWESOME acting voice’, they KNOW. They just KNOW. In their little heads they go…”Yep, you’re trying to teach me something. I’m not having it Mum. Sod off. This bit of card that’s been on the floor for three days has suddenly taken my interest.”
So what do you do? Here’s what you do. You set up the activity while they are busy/asleep/out and then when ready you START TO PLAY YOURSELF. And when they approach you say casually, “Do you want to try/play too?” and once you’ve got their interest you start to explain what to do.
It is crucial at this point to try and do something SILLY. Get it wrong yourself, laugh, make a funny noise. Engage the child at their level of fun. You want them to think “Mummy is PLAYING and I want to play this too.”
The golden rule? Never force it.
If they come, great, if they don’t leave the activity out if you can. They might approach it later. They might not. It doesn’t matter. It’s 5 minutes.