You can tell a lot about a person by the book they are reading.
With kindle mobile app no-one will judge you by the cover of the book in your hand.
Dave Day time TV
Setting: Woman reading "Games you can play with your pussy" on the central line at 8:30am on her way to work
More ident ideas:
Setting: Sat on the 7:35 bus to work with a bunch of school kids reading "How to raise your IQ by eating gifted children".
Setting: Sat in the Lawyer's office waiting room reading "If someone lies to you, murder him and lie about murdering him".