You tell your audience that unlike the so-called fingerprint experts, YOU are able to read fingerprints, rather like a palm reader. You hand out 5 envelopes and slips of paper to random members of your audience. Each writes their name on the slip and seals it in the envelope. Next they each place their thumbprint onto the envelope. The envelopes are collected by a member of the audience, mixed up and then handed back to you.
You are now able do a reading from each thumbprint from which you are able to give a physical description of the thumbprint’s owner and hand it back to them.
After all 5 have been read and handed back the volunteers open the envelopes and all 5 are found to have their correct thumbprint.
An unusual and entertaining presentation.