Thanks for the great suggestions, ladies.
Isn't it amazing how few "quiet" toys there are out there? I was looking through several stores and it seemed every single toy that might have worked made at least some sort of noise - I wonder why that is?
We have a large selection of pop up books and lift the flap books. We rotate these out. I also bring a small spiral of notepaper and a pencil. My DS loves to 'take notes'. We have also used sticker books and lacing cards.
I had just thought of the small spiral notebook idea at the last minute. It kept him quite happy through most of Palm Sunday church - yay! We got some washable crayons from a restaurant one time that I used with it, and he drew some blue on his knee, so we'll see if they really are washable.
Does the pencil wash out of clothes?
He likes lift-the flap books - Does anyone know specifically of any pop-up or pull-tab books that would be small and/or in board book form? I didn't think of the lacing cards and stickers - more ideas to rotate from - awesome!
Aside from church (although even this doesn't nec always require complete silence - kids will be kids) I think it should be fine if your lo makes some noise, like animal noises. Or is he just very loud when he does it??
People actually smile at it and think it's cute - I don't mind if he does it once or twice, and we're working on teaching him to at least talk in a whisper when he does it. But he very much likes to do it repeatedly (for effect, of course), and the only things to do to stop him is either to walk out to the back of church or to quickly distract him with something. We actually did not have to leave even once yesterday because I kept whipping out new activities - yay! We do have "cry rooms" where people can sit with children, but I typically find that a lot of the parents who sit back there do allow their children more freedom than I want ds to assume at church, so I want him to have a different example to learn from.
Thanks again for the helpful ideas - let me know if anything else comes to mind!