Instead of getting each person to devise their own position, you devise positions per keyword and when the keyword is mentioned everybody has to take that position.
You can extend the game by making the last person to take up the position undergo a forfeit such as take a drink or do something.
Umbrella = position with hands making an umbrella with their hands
Grenade = everybody dives to the floor
Holmes = every starts inspecting walls for clues
Goallllllll = everybody makes a great goal has been scored
Timber = everybody squats holding their heads
What you need
- No props required