We used to do that when I was young. Local headshop sold the nitrous cartridges, the thingy ma-do to discharge them, and BIG balloons lol. I can remember more then once filling up a HUGE balloon, and taking my first hit, only to get so messed up that i'd pass out and let go of the rest of the balloon and it would go flying around the room LOL. Good times. They called it hippy crack. I've seen em online as well, but its just not my cup of tea anymore. I hate the zonked feeling they would leave me with, and sometimes headaches. But ya think your out for 30 minutes, when it was really only 30 seconds hehe. And that sound....WAWAWAWAWAWAWAWAWAWAWAWAWAWAWAWWAA! LOL