Let's imagine a future in which a truly intelligent computer program exists. How would it convince us (humanity) that it was intelligent? Alan Turing's answer to this question, proposed over 60 years ago, is that the program could convince a human conversational partner that it, the computer, was in fact a human. 60 years later, the Turing Test endures as a gold standard of artificial intelligence. It hasn't been beaten, either--yet.

Relevant links:
https://en.wikipedia.org/wiki/Turing_test
http://commonsensereasoning.org/winograd.html
http://consumerist.com/2015/09/29/its-not-just-you-robots-are-also-bad-at-assembling-ikea-furniture/