Theory11 - Rick Lax - Hair Tie Coloration

Here's a quick trick catches people by surprise. In fact, the switch is so smooth, so impossible, that people do not even realize it happened until you point it out to them. Then they freak out.
Pull out two of your girlfriend's hair ties, differently colored, and explain, "Whenever she leaves something at my apartment, I turn it into a magic trick. Now let me show you what I came up with using these ..."
You wrap one hair tie around the spectator's finger, keeping the other one for yourself. You ask the spectator to touch her finger to her thumb, so there's no way you can get to the tie.
And then, before she knows what hits her, THE HAIR TIES HAVE ALREADY SWITCHED PLACES.
Fast, easy, and more colorful than a rubber band trick.