Get an old scrap hard drive that barely works except for the motor or has almost no memory. It would be a shame to waste a good hard drive on a device to annoy your little brother or sister or parents.
Have you even read the rest of the post?
You also obviously have no idea how many scrap hard drives we all have lying around - I can see at least 10 from here. Some are broken, some are just less than 40GB or so and about 10 years old - I'm not going to trust my data on one of them...