At one point during my teaching career I used a cardboard box, the top of a plastic bottle and a toilet roll tube to make a random answer generator. A ping-pong ball went in the top and would then either go into the green pocket on one side, or the red pocket on the other. It was great for language points where there are 2 options, such as "I like.../I don't like..." or "I can.../I can't...". It worked like a slightly more exiting version of heads or tails. Sadly, I had to leave my amazing creation in China. So I thought I would make a powerpoint version that can go with me anywhere. It's not quite as random as the original, but the students don't know that!
Press the "fill" button as soon as you've started the presentation. Then the "lunch" button will appear. Press this to release a ball and see which side it goes to. Don't forget to assign a language point to each side and then have the students produce the appropriate sentence.