Fun chemistry experiments?

My Ap chemistry cl is going to do some demonstrations for a bunch of 5th graders. So we need some "showy" experiments to do (like colorful or some thing cool happens). The only problem is that we can't use fire. I already have a couple (elephant toothpaste, sulfuric acid and sugar) that we are going to do but do any of you guys have any other ideas? And i mean more advanced than a baking soda volcano, we got a cabinet full of chemicals we can use!