You need warm up games for 5 year olds?? One of the main objectives for doing warm up games for older people is to put their mindsets into the time when they were 4 or 5 years old. But you do need a game that will overcome any shyness and make everyone feel included. This is a game I've played which as it happens covers physical & vocal warmups. Its a veryation of musical statues.
Everyone runs around the room (being aware of other people, no head banging thankyou) The leader calls out the name of an animal and everyone makes a statue of that animal. After you've run out of animals instead of making a statue they have to make the noise. Then the statue and the noise then into pairs one makes the statue one makes the noise, then into threes and fours, get all four making the statue and the noise of the cow. Split the class into two see who can make the best, most realistic loudest horse, dog, pig or elephant. Add some other noisy objects into the mix, cars, motobikes, trees in the wind, rivers, machine guns, fireworks (interesting statues on this one) and the old favorate the toilet - if this one provokes a lot of laughter you know you've got them on your side.
This game can last any thing from a 5 minute quick up to a whole session during which time you can start introducing realistic scenareos into the game.