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.
Dead Giveaway is the first. The room code, the phones and the scoreboard are shared plumbing, so the next game is a shorter build than this one was.