I would try to nip this right away. My son turned 2 in November (he's very active too) and when he turned 1, we put him right up to the table (we bought a space saver high chair/convertible booster seat...$20ish at Walmart/Target...as we have no room for an actual high chair- if you do not want to purchase a new booster seat, do what we do at my parent's house, we take two dish towels and tie them together and then make a make-shift seat belt that we tie behind the chair.) and he was strapped in. When he turned 2, we stopped strapping him in, but he is learning that if he stands up in his chair or tries to get down, he gets 1 warning/reminder to sit in his chair and then he gets strapped in again for the remainder of dinner! It works really well so that he can reach the table fine and have some independence, but we can have some control of the situation thanks to the safety belt. Kids this age should be able to LEARN how to sit for at least 20 minutes or so...we even ask him to sit a little longer if we have guests who eat a little slower than we do (reminding him, it is nice to eat together...when we are all done, you can get down!). We also ask him to ask to be excused. We do tend to have the TV in the background- low volume, not really watching it...my hubby just has something about turning off and on the TV-, so as someone previous mentioned, if that helps him stay put until everyone else is done, it might be worth trying (maybe say, now that you are done eating, would you like me to turn it to a show you would like while the rest of us finish up). You can also include him in the conversations going on at the table and that will make him feel included. You could also do what you would do at a restaurant...books, toys, color crayons and paper...after he finishes eating to keep him occupied as well. I don't think it is unreasonable to expect him to sit for a little bit with the family without running about.