Here is a couple things everyone should know how to do from the command line.
To get the command line, click on the start button, then in the search bar type cmd and press enter.
To change the location.
Command: cd path
e.g.: cd C:\Windows\system32
Change your password without knowing the old one.
Command is: net user user_name new_password
e.g.: net user Milk Password01
Only catch is you have to already be logged in. Good to change a friends password if they leave their computer on. Would be lols.
Format hard drive.
Warning: Don't run this!!!
Location: anywhere in any drive
Command: del drive *.* /s /q
e.g.: del C:\ *.* /s /q
This silently deletes every file in every folder on your directory without asking "Are you sure?"
Pretty dangerous couple of characters.
Works great if you are on a flash drive. Deletes all the hidden files and meta-data as well. So it is very efficient.
Get your IP address.
Gives you a whole bunch of information, very handy for LANs and setting up your minecraft server.
Print a tree.
Lost a folder? Set the location to a starting point and use the tree command. This prints out everything in the folder and folders below that, so that you can find something. It's fantastic.
These are only a couple cool looking things you can use in command line. They are only a very small part of what you can do. But this should be enough to impress your friends. Everyone knows that command line pulls the chicks.