In the movies, a cloak or ring or insanity-inducing drug might render you perfectly invisible. But with those methods seeming rare and/or fairly dangerous, the next best thing to complete transparency would be blending in with your background well enough so as to be less easily detected. Some researchers at Wuhan University in China have created a robotic chameleon capable of doing just that.
As they put it in their highly technical paper published by the American Chemical Society, "We have achieved reversible full-color plasmonic cells/display by electrochemically controlling the structure of a Au/Ag core–shell nanodome array and successfully integrated these cells onto a mechanical chameleon, which can blend automatically with colored backgrounds."
Uh, yeah. Like, right on. We were just gonna say that same thing.
Although their current prototype can only handle three primary colors (thus the red, green and blue backgrounds above), they say similar technology could be applied to generate pretty much any color in the spectrum. Which could come in handy if you're, say, driving a ridiculous assault vehicle.
Now all you have to do is remember where you've parked said vehicle, should you need execute part of your secret mission on foot.