I've been asked to share what things we have done to encourage good table manners in our home. This is one area where having older children makes things so much easier. For the last several children, table manners have been learned much more by observation than anything. We still train our younger children, but so much is just picked-up by watching their older brothers and sisters. So, to really answer the question, I have to think back to when I only had small children and try to remember what we did.
We started out with just a few rules: 1. We eat sitting down. 2. We keep our food on our plates. 3. We do not complain about our food. If a child didn't follow one of these rules, we decided they must be done with dinner and cleared their plate. When I asked my olders if they remember anything specific about learning table manners, M. specifically mentioned having her plate removed. (Though with M., I'm pretty sure we only had to do it once.) The key is to do it without drama. When I have to remove a plate (and I'm sure I've done it to each child at least once), I calmly say, "Since you got up from the table (or threw your food or must not like it), you must be done with dinner." and whisk their plate away. Most often this is met with stunned silence, sometimes followed by wailing, especially if they weren't really done. But we have found, with consistency, children learn pretty quickly what is and isn't expected.
Of course, over the years, we have had to add other, fairly specific rules, such as, don't touch your feet at the table, no singing at the table (yes, our children will just break out, loudly, in song, which can be fun at first, but difficult to talk over), and don't use the tablecloth as a napkin. If table manners have really descended to the depths, I will break out our framed list of rules good table etiquette (which is displayed along with 'home etiquette' and 'daily life etiquette') and do a dramatic reading for the assembled family.
But, I think, one of the best ways to make family dinners enjoyable is to make them a positive experience. A family dinner is not the place for arguments or disagreeableness on the part of parents or children. It is a place for interesting discussion and fellowship with one another. If your family is not experienced with dinner table discussion, it is best to have a game plan. We have done many different things throughout the years to facilitate discussions. One idea that even the littlest can participate in is to ask each person the best and worst part of their day. Even K., before he could really speak in sentences, could share that his favorite part of the day was playing with cars and his least favorite was napping. We make sure that everyone listens to each other when they are sharing. The littles particularly like this because they are often drowned out in the other hubbub. Other things we have done is to use discussion cards with different questions for each person to answer; asking everyone's opinion about a news story; or asking what new thing each person learned that day (adults, too). These days, we don't often have difficulty finding things to talk about...the blessing of having older children.
What time we have dinner is also something people wondered about. We tend to eat late, often ~7pm. My ideal time would be 6:30, but the babies both want to nurse right about the time I should be fixing dinner, so it throws the whole meal preparation-thing off. For much of our parenting life, J. needed to work until 6:30, so we would eat a later dinner when he arrived home. Due to demands at work, he still often arrives home after 6:30, so the later dinner hour works. The children are all used to eating later, but many will still choose to have a piece of fruit in the late afternoon to tide them over until dinner. Because we homeschool, we don't have to be up as early as many people, so our entire schedule can be a bit later. J. also teaches night classes at least once a week, and in some seasons he has taught more. I still eat dinner with the children even when J. is not home, though I admit to easier dinners on those nights. (Scrambled eggs and toast make a very acceptable dinner, in my book.) This, too, has become easier to manage with older children. It's difficult to carry the entire conversational burden when one is the only adult with a table of children 5 and younger.
Oh, and to everyone wondering about how we filled out the census...I just went in chronological order. I figure they'll call me if they want more information on the youngest five. At least there were enough spaces for everyone in our family. It would be weird to leave someone off.