Roolz: It must be scientific, it must be possible with today's technology (that means no teleporting, hover cars, or time machines) and it can't actually be that entirely useful.
EM Spectra Goggles:
I sorta want goggles that have cameras on each lens that can read the entire electromagnetic spectrum, then filters out everything except a certain region and shows it on a screen in front of my eyes. By default, this is visible light, but a slider could control which area we see, so I could shift it to radio waves and see WiFi networks :D