1, Karl Power
He became well known for appearing uninvited at sporting events as an imposter. Most famously he appeared in the Manchester United team photo before a Champions League match against Bayern Munich in 2001. Power had entered the stadium pretending to be with a TV crew to gain access to the pitch and simply walked back to the stands again afterwards to watch the game.
http://www.youtube.com/watch?v=dfg-5l_z7yc
2, Guy Goma
Guy Goma was waiting in the main reception area of the BBC Television Centre to be interviewed for a position as a "Data Support Cleanser" in the corporation's IT department. At the same time, Guy Kewney, a British technology expert, was in another reception area, preparing for a live television interview. The producer who was sent to fetch Kewney, however, was told that Kewney was in the main reception area. When he got there and asked the receptionist in person where Guy Kewney was, she pointed to Goma, even after being asked if she was sure that this was the right person.
So he approached Goma and asked him if he was 'Guy'. Hearing his first name, Goma answered in the affirmative. Goma was led to the News 24 studio. BBC staffers put on makeup, and he was ushered to the television studio, where he was seated in front of the cameras and wired up with a microphone. Although believing the situation to be highly unusual, he prepared to do his best for what he believed would be his job interview.
When introduced by interviewer Karen Bowerman as Internet expert Guy Kewney, Goma became visibly shocked as he finally realised the serious misunderstanding that had taken place. Aware of the fact that he was on live television and not wishing to make a scene now that the interview had already begun, he simply played along, doing his best to answer the interviewer's . Apart from the facial expression at the start, the interview seemed fairly believable to many viewers, particularly those unfamiliar with Kewney.
http://www.youtube.com/watch?v=l5evS-ApSNQ
3, Thamsanqa Jantjie
Millions of TV viewers saw Jantjie, 34, interpreting speeches by Barack Obama and other global leaders at the FNB stadium in Johannesburg. His gestures baffled and angered deaf people around the world, with experts saying he did not know even basic signs such as "thank you" or "Mandela".
http://www.youtube.com/watch?v=NpPvGP_GUXs