I think I'll start by just adding replies to this thread with different useful tasks and how to accomplish them, and if they're any good then perhaps ask to have a forum mod spawn them as their own thread post.
Fun Things You Can Do (that you probably didn't know about)
Table of Contents:
- Make a disk or volume READONLY so people can't delete your files easily.
- Invisible files with Alternate Data Streams (ADS; Alt Streams) on NTFS volumes.
- Shortcuts and symbolic links to files and folders, the various types, and their behaviors.