I call this the reporter routine. I just made it up on the spot, spontaneously.

Root: Say you are a reporter, journalist, food inspector, whatever. It helps if you have props. I used a clip board and camera I borrowed from some friends.

Opener: Introduce yourself as a reporter or whatever profession you choose.

Time constraint: Say you only have a few minutes but you would like to do a short interview.

Hook: ask interesting questions about whatever venue you are at. I was at a rugby game so I asked a two set about what it is like watching rugby.

Close: say you need to go but you would like to interview them further and you need their number.

After you get their number tell them you were just practicing your acting skills and you are not really a reporter. If done right they should laugh.

Be careful with the food inspector one. I tried it in a restaurant and told them there was pubes and fingernails in the food. They believed me so I left and one of them ran after me in the parking lot yelling at me to come back.