All joking aside, there are numerous ways to shut down Windows 8 using the GUI. (The old command-line shutdown.exe is still an option as well, which you can run from the Run box, Win+R, or by using a normal command prompt.)
Here are some other options:
• If you log out of the machine, you will see power options enabling shutdown (see screen shot below).
• Select Settings on the Charms bar (Win+C), then shut down via the Power button. You can also open Settings directly by pressing Win+I.
• Press Ctrl+Alt+Del, then use the power button in the bottom right corner.
• Most new machines will also let you just push the power button on your machine, which will either power off, hibernate, or put your machine to sleep depending on your power configuration.