Here's one you might enjoy.
I think the Gaff Decks are a lot about your imagination and your presentation, these aren't just your run of the mill magic effects where you can say
Here, I have the Jack of Clubs
< 2-3 seconds later>
Here, it's now completely blank.
Now whilst the look of it might be alright and the blankness can be a bit of a shock. To people who have seen your magic before, it's just another colour change. So what can you do to enhance something simple like this? Use your imagination!! Say you're going to suck the image right off the card and place it somewhere else (maybe on a double blank card you've loaded into the spectators wallet at some point?) Granted you may want to remind them that it is the card they picked at "random"
I'll use an example that has gotten me great reactions and is the one I'm known for around my school.
A Royal Death
Effect: The performer shows the spectator the King of Hearts and points out the fact that it is stabbing itself in the head. The performer makes a point of how it is the only King that does this in almost any deck of playing cards (the spectator may view the others if their untrusting mind so desires). "But surely!" the performer says "If he's still alive, as he is now...That sword has really gotta hurt!!" Most spectators will at this point either agree or run away thinking you are a crazed psychopath. The perfomer continues "Let's help him out shall we?" The spectator is invited to hold out their hand and hold the King. After a few mystical gestures the spectator says they can feel something, a tingling sensation. Almost one full minute later, the spectator is reminded of the situation, one alive and kicking suicidal king with one spitting headache. The spectator is instructed to look at the King they hold, and (usually with a scream or two) they find that the King has become naught but bone; a 'Skull King' if you will.
Patter
Performer: Here, let me show you something a little strange. I promise you it's perfectly safe. Take a look at this King of Hearts, do you notice anything a little odd about it?
Spectator: Not really...
Performer: Most people don't. If you take a closer look though, you can see that this King is stabbing himself in his own head! Not a single other King in the deck does this. He is known as the suicide king, for obvious reasons; some say it was over his wife, the Queen of Hearts whom he found with the Knave doing unspeakable things. Either way, that sword has really got to hurt right?
Spectator: *shows some sign of agreement*
Performer: Great! Could you hold out your hand for me? Just that one will do.
Spectator: *does as they are told*
Performer: Now, if you could just let this King lay on the palm of your hand. I promise you this won't hurt and nothing bad will happen to you, but you must let me know if you feel something. Some people do, some people don't but just stay very still.
The performer makes motions underneath the spectators hand that look as if he/she is draining an energy from it.
Performer: Did you feel that?
Spectator: (usually) Yes! Oh my God! It's tingling!
Performer: That's okay, it's working. Just let me know if it starts to hurt.
5 -7 seconds later
Performer: *appearing the slightest of drained* Okay, I think it's been done. Remember before, the King was stabbing himself in the head?...Take a look.
Spectator: *screams/drops the card* Oh my God! How!! How did you do that?! *head explodes*
~ Fin
Obviously the reaction varies from person to person and never have I seen anyone's head explode over it. But I have had big screams and the card being thrown at me. Those of you who own Derren Brown's Tricks of the Mind book will recognise the presupposition. And those with experience in suggestion and/or mentalism will see how the effect works to a point where the spectator can actually feel something happening. I won't post the workings of the effect here, but if you have any questions feel free to PM me about it and I'll do my utmost to answer them.
Hope I've helped a little here.
- Sean