This can be used during the game time that your already awesome class already earned. The bonus of using this game is that it is silent (and if it is not silent no one plays) so everyone wins!
1) Find something that you can let the kids toss around some good options are a spongy dodge ball from the gym, a stress ball, or failing all others a crushed up ball of paper. Some terrible options are that gerbil ball with the gerbil still in it, anything breakable, or anything heavy that could break something.
2) Explain the rules (which are simple). You throw the ball and if the person catches it everyone is still in. If the person does not catch it the game commissioner (the teacher) makes the all important call. Was t a bad throw that the other person could never catch? The thrower is out. Was it a great throw and the catcher was too busy staring off into space to catch it? The catcher is out. PLUS if anyone talks or makes a peep at any point then the talker is out.
3) The kids spread out around the room and you toss one of them the ball to get things started.
4) As the kids get out they sit at their desks (or if it's the end of the day and chairs are up they can just sit on the floor).
And that's basically it.
The game can get a little boring when you are down to only a few kids so usually around the 5 kids left mark I like to throw them some curve balls. Tell them they are all t-rex and have to keep their elbows stuck to the sides of their bodies at all times, tell them they are only allowed to use one arm for catching and throwing, tell them they have to do hand/head stands and catch the ball with their feet, or just find another way to make it slightly more trickier for them.
And obviously, remember to have fun. If one of the kids want to be the games commissioner then you get to show off your mad silent ball skills.