Reset your graphics driver – Win + CTRL + SHIFT + B

Remembering a wifi password you entered forever ago:
c:\> netsh wlan show profile
< shows a list of wifi profiles you have connected to >
c:\> netsh wlan show profile <wifiProfileName> key=clear
< shows the wifi password you last entered >

Message every single windows system on the network
c:\> msg * <message>

Hackertyper – Hit F11 to fullscreen your browser and then look like a hacker.
https://hackertyper.net/

FakeUpdate – go to the website, get on your friend’s computer, load the update screen for that OS, hit F11 to go fullscreen, and then see how long they’ll sit there before resetting.
https://fakeupdate.net/