this one's really dumb.
so I get playing cards or when ever people are playing cards or whatever and I shuffle them and ask someone to pick a card any card. They get one out memorize it and put it back. I shuffle up again then sit the deck aside, or maybe pull my sleeves up or maybe throw the whole deck over my shoulder but that's messy. anyway I just do something fancy. Then I reach into my pocket like I'm looking for something and pull out my wallet hold it out and say "is this my wallet?" and that's it. instead you could even go into the wallet like the card's going to be in there, pull out a picture and go "is this my dog" or "is this my son". You've got to say it all sly like you've done something great and look around at everyone like, "did you see".
It's dumb but I like doing it to people.