Moroccan handcuffs

Her hands are tied (by uninitiated spectators) with a leather strap.
>>> But you'll be free again within seconds!

This makes many effects possible. Of course, this includes numerous escape illusions—from sacks, suitcases, or boxes—but also highly amusing routines, such as Eddie Burke's:
Your hands are tied behind your back. A broom handle is slid between your arms and held by a spectator on either side. You chat with the audience, taking a few steps to the side. Your audience looks amusedly at the two spectators who are still holding the broom handle, completely astonished to see that you were able to free yourself while your hands remain perfectly bound.

Then you have rings handed to you that seem to pierce the shackles... and so on and so forth.

Definitely the best entertainment for any audience and completely inscrutable.