Cathy has her own trick for keeping her daughter occupied while eating out:
I created a restaurant survival kit custom made for my toddler. I bought a plastic pencil box and filled it with a pad of paper, washable crayons, and (most importantly) stickers. She does not have access to stickers at any other time, so they really keep her attention. The items you put in your kit definitely depend on your kid, but from about 2 on, our daughter became so engrossed with peeling stickers that she was completely silent and occupied until our food came. You will have to peel the backing off the sticker sheets to keep your kid from becoming frustrated and throwing a tantrum.
Here are a few more toddler-in-restaurant ideas.