The things that you can do with an old hard drive is virtually limitless. If it’s beyond repair, then you can have it taken apart and salvaged for parts. You could sell the components, or use it to create hard drive works of art, like the Shadow of the Colossus hard drive. If you’re not very artsy, then you could mod it so you can use it as a paper weight, door stopper, or a book end.
However, if you’re particularly handy with tools and have a sweet tooth, then you might want to embark on a little DIY project and turn it into a cotton candy machine instead.