Open a game on the TV. Everyone else scans a code and plays from their phone. No apps, no accounts, no cost — just the browser you already have open.
Everyone answers the same prompt anonymously. The room guesses who wrote what. You score for guessing right — and for every person you fooled.
Two castles, one field. Train troops, march them across the map and knock the other wall down — every order lands on a five-second beat, so it is a battle of nerve and not of thumbs.
Everybody is a different body part of one enormous floppy creature. One phone is the left leg. Another is the right. Somebody is the head, and only they can see round the corner. Now make it walk.
Everybody draws one body part of an animal they never see whole — you only get the seam. The TV stitches them together, the creature walks out on its own legs, and the room votes on it.