hm, but, what it basically comes down to would be dressing up weird / attention grabbing / special (be it with sunglasses, strange headwear, or .. big wooly boots), with a bunch of people?
i dunno, but that's not really a mindfuck--yet, IMO.
still needs some kind of "hook", otherwise people will just go "bunch of persons wearing sunglasses", something funny, that connects something in an unexpected way.
maybe if you buy a bunch of real cheap sunglasses in bulk, and leave them in a box in the men's and ladies room of a club / bar, start wearing them with 4-5 people, see how many copy?
it also depends on where you are, of course. in a big city, you can dress up as weird as you want, even in a group with 10 people, the public will just go "whatever". while in a smaller village, you can probably still surprise people with something like this.