Did you know, through, you can make a hidden directory?
You can also do this in the Terminal with:
cd /home/admin/Desktop
mkdir .hidden

We will do the graphical way.
Note: This tutorial can also been performed on a Mac.

Right Click somewhere on your computer (in /home/yourname) and click Make Directory.
Let's do that on the Desktop (/home/yourname/Desktop).

Give it a name.
Note: To make the directory hidden, ALWAYS start the (file)name with a dot.

You don't see it!
That's because your directory has started with a dot.
Let's get an access to it!

Go to /home/yourname/Desktop.
Wait a sec... The directory is still hidden!
Not a problem at all!

Just press CTRL+H, or like it's shown here, click Screen (or whatever it says) -> Show hidden files.

And here it is!
Have fun tricking your mom with porn (and tell her you don't have any porn). :P

By default, only a root can see hidden files.
But in the world of Linux, everything is possible!
Hidden files and hidden directories are very handy, escappely if your laptop has been ripped from the police.