Lots of the above! My new avatar is a pic of DS transferring veggies I had chopped and left on the tray for him to put into the casserole dish. I let him put potatoes in the pot, stir sauces and things with my help,. I pull his highchair up to the counter backwards and he stands on it and that way can't get out, and let him do things like that. Most often when he is done he inches over to the sink and I turn the water on for him and he plays - he likes letting measuring cups fill up and then dump them into an empty pitcher. (And then dump 2L of water on my floor!!! Good thing he likes mopping, too!)
I also have homemade playdoh which is just flour, salt and water and if I need him to stay helping and not run off quite yet then I get that out and he can play with it on the counter top while I continue making dinner. That way it's not getting real playdoh into our food by accident, if he does get some in, it's only dough!