BigBrother is the greatest prank to hit the iPhone! This simple prank will provide entertainment to you and your friends for hours.
Instructions:
Begin typing in the "Engage" box. Touch the invisible black button to the right of the "submit" button and then type the answer to the question. After you are finished typing the answer, touch the black space again and finish typing "Big Brother, please answer this question:"
Type the question and push submit. Stand back as your friends freak out.

Engage
(secret button) answer to your question (secret button)

Question
Type the question that you answered in the box above.

If you need this explained further, search "Big Brother iPhone app" on YouTube.