I think it must have crossed the mind of every person who's played Portal what they'd do if they had a Portal gun. Me, I'd put one portal in Chicago, another in Bath, and then smash the gun so they'd never get removed. Oh, how I yearn for teleportation to the States. But it does seem reasonably obvious that after about, maybe five minutes, we'd all start using them for practical jokes. Take a look at the video below from YouTube SFXers Final Cut King and the VFX Bro.
And that screen of gibberish that flashes up? I don't have the energy, but if you do, it's here: