One common prank I've been a part of is producing fake blue screens of death. It's known as being easy (take an image of a blue screen, put it in a slide program, and maybe add some random jumpscare or sound effect triggers) and is effective without "going too far". Nobody suspects the gal wearing the blue screen of death t-shirt, not even this year.

Also, someone saw I was still technically mourning from loss this week and gave me a fake lottery ticket thinking it would cheer me up. Har har har, I fell for it. Even asked someone for an on-the-fly ride to the store only to learn right then and there at the store I've been bamboozled (and now owe the person who rode me there ride money because I told him I'd pay him in some of the lotto winnings).