The challenge is to do it with a normal deck and no preparation. It would be quite difficult to do with a gimmick too (and as far as I know I've never seen one)or.. easier.. a tricked card.
A spectator picks a card. You put it face down halfway the facedown deck, but you insert the short side of the card in the long side of the deck. You push in and, being the short side... shorter... it pops on the other side face up! No strange moves or switches.. the spectator himself could pull it out! possible?

I've toyed with this idea without much success.

I may be wrong here but I was told years ago that Ken Krenzel may have done an effect like this.
Not much more info on this effect however.

Same for me. I always think of it when I'm relaxing with my deck in my hand... It would be really a good effect, so impressive.
The best way I could make it is with a gimmick and sleight of hand and still it's not as clean as I described. In Hiddenly you turn the first card of the pack so you have both sides showing the back. You force the card and force the signature in the upper 3/4 of te card. You put the card face up inside the deck face down. It catches the gimmick (half card "pocket" with the top external side glued toghether, but not sides). So you play back and forward (not pulling the back side more than half) and it looks like as I described the effect. At some point you leave it half way through. Sceretly turn 180 degrees the deck. Now the audience sees the front of the gimmick (the forced card without signature sticks out for 1/4). You push the gimmick in and the good card pops out showing the back to the audience, turn it and you're done.
I know.. is far from what I've asked... but is just what I could get to

Hey Marcello,

I think I might have came up with a solution to your with using just a regular deck. PM me and I will let you in on what I came up with.....

You insert 3 face down cards in that fashion, and the middle card turn face up when pulled out from the other side. There are several versions for this effect including Nick Trost's.

Hideo Kato

I want to change it going across the side (like making a cross.. not on the long side). Please view my video done with the gimmick

http://www.siroma.com/magic/b2f.wmv