This was the best April Fool joke I ever did.
I was Customer Service Manager in a large call-centre, working for a company that was contracted to ITV to provide call centre operations. In each wing of the centre there was a large photocopier and scanner. These were used a lot for scanning documents in, and general clerical stuff to do with customer accounts. They were concealed from the main area by a moveable screen. One day, we got some new ones in. They just happened to come into service on April 1st.
That morning, I sent out a memo to all my team leaders. "We have installed new photocopiers in Green Wing, which are state-of-the-art and voice-controlled. They are very simple to use and should save the teams a lot of wasted time dealing with all the buttons on the old ones. Please brief this to all teams during the pre-shift briefing: ..." I can't remember how it went after that, but it was mainly telling them to put the original on the glass bed, close the lid and then say "Print" in a clear voice. If the machine didn't respond, you weren't speaking loudly or clearly enough. I think I refined it with commands like "Add Paper" and "No, not that paper, I said A3" and things like that.
Then I retired to my desk and waited.
It was a complete riot and an unmitigated success. All morning people were disappearing behind the screens and then you could hear, louder and louder, "Print. Print. Purrrrrint. PRINT! Look, just fucking print, OK?" One girl eventually started to say 'please', which spoke well of her upbringing, but nothing for her common sense. After a while, most people had got the joke and were just waiting for yet another innocent to go behind the screen and try their luck. People had tears in their eyes, and calls to ITV that morning were not answered with our customary professionalism.
I was really proud of that one. Have a good day, and don't be fooled. Not by anyone.