Don't flush sodium down the toilet. I've actually been told that before. Chemistry teachers routinely say it, which only makes students want to do it. Instead, watch two mad scientists with YouTube channels do it for us. Grant Thompson, the "King of Random" (previously at Neatorama) teamed up with CodyDon Reeder (previously at Neatorama) to flush sodium down a toilet to show us what will happen.
My brother told the tale of how some "friends of his" tossed sodium into their college dorm toilet for fun many years ago. The toilet would routinely throw the sodium chunk back at them. Then some fool got the bright idea to flush it, and you now know what happened. The administration never pinpointed who was responsible, but every resident of that building got a good dressing-down. -via Digg