Even more idiotic than waving to someone waving to someone behind you, and a lot harder to take back or disguise. See also Awkward.
Ways to cover up your idiocy include pretending to fix your hair, scratch your head, or pointing towards nothing. See also Awkward.
A box social in the United states is a form of fundraiser, wherein donated lunch boxes are auctioned off for a cause (often a civic, church, or school charity). Usually a woman creates a lunch, which is then auctioned off. Varying somewhat, the custom was for the person who had prepared or donated the box lunch to go on a date with the person who won the lunch with the highest bid, or at the event sit with that person and share the lunch. See also Awkward, Old-Timey.