Matchsticks
One match moves. Find which.
A false equation drawn in matches — or a number to make as big, or as small, as one match allows. Everyone picks a match up on their own screen and lays it somewhere else: the answer pays most, the next best numbers a little less, and the clock adds to it. Or play it aloud: first to buzz says which match moves and where, and the host says right or wrong. Every puzzle is dealt fresh, so the evening never runs out, and every one has an answer.
You run the table. The others just have to join.