Ghost

There are lots of files on your computer that you can't see. Apple has conveniently hidden many system files from you, so that your computer doesn't look like an ugly, cluttered mess.

However, they have not provided any easy way to create your own hidden files, or even to view theirs. Ghost provides a simple, user friendly way to do both of these things. Simply drag and drop a file or folder into the list, then uncheck (or check) its checkbox and the item will be instantly hidden or un-hidden.