They are mostly board and need some distraction which is a good time to sell to them.
Build a local wifi network on the vehicles of the public transportation (tram, bus, etc.), incentivize the travelers to connect by giving them discounts, achievements badges, etc. Have special exclusive offers and content only available there. Monitor their behavior to personalize your communications with them. Share revenues with the transportation company.
From time to time, there is an auction for a meeting or talk with a pubic figure. The problem with this auction model is, that only people with money can contribute and only they can win the auction.
Instead of one person donating a large sum, have people donate smaller amounts (or larger ones if they want), and instead of an auction, have a raffle and a winner. Each person donating has the same chance, and you get all of the donations for the charity.
Aren’t you interested in what famous, rich and successful people’s typical day looks like?
Have a video series where each episode is dedicated to such a person, and show their days.
To get to know other surprising facets of well-known figures in their fields (authors, actors, entrepreneurs, politicians etc.)
A dedicated publication with one new surprising fact about on public figure a day.
Let the visitors express their viewpoint.
Have a simple mechanism for visitors to vote for the art they like or dislike. It can be as simple as a button on the wall beside the art, or even a smartphone app.