Phoney (Telephone Directory Test) by Trevor Dawson

Effect:
A local Telephone Directory is shown to a spectator, who freely selects and notes a subscriber's name, exchange and telephone number. We would stress that the spectator can choose any page and any column on that page. The Directory is placed down and immediately the performer knows the freely chosen entry for revelation in any manner he desires.

There just can not be a more direct effect because, as the spectator makes his choice, the performer is automatically in possession of the same knowledge without the need for it to be written down