If you smoke, the smoke waterfall is neat and easy.
Take your pack of cigarettes and pull the cellophane down to create some space between the cellophane and the box. Using your lit cigarette, carefully melt two holes on the lengthwise ends of the cellophane, and then push the cigarette lit end first into one of them. If done right, the smoke coming off the cigarette will make a little waterfall and pool of smoke.