The performer throws a paper ball into the audience. The person who catches the paper ball joins you on stage. You introduce a prediction envelope and a file that contains a list of hotels and their addresses.
Phase 1 - The spectator thinks of one hotel from the list. You tell him that these hotels are located in 4 different countries. He locates those 4 addresses of his thought-of hotel one by one as per your instructions and looks at the flags of those countries. Eventually he selects a flag of one country. You open the prediction envelope and show him that there are four cards with the name and flag of 4 different countries, but one card has a different back design - this card happens to be his selected country.
Phase 2 - Ask him to concentrate on the hotel he is thinking of. Without asking any questions, you directly reveal the hotel he is merely thinking of.
Phase 3 - You ask him to locate the address of thought-of hotel of his selected country. He adds the Postbox numbers together, and that total matches the number written down inside the paper ball that you had thrown to him in the beginning.
Three amazing phases, each building to a super mentalism finale. Spectators will admire your powers!