I did this with my kids last night because we just finished reading The Swiss Family Robinson and the movie was going to be playing on tv during dinnertime, so we decided to make an event of it. I spread out a tablecloth on the floor, made dinner as usual and just put the plates on the floor. We got to watch our movie, eat our dinner, and then clean-up was a snap! The kids loved the change of pace and I enjoyed it as well.
Go on, it's a lovely day for a picnic!