Looking for any ideas for a couple free touchscreens in a museum environment. The screens are running on Mac minis.

We had a custom-built app running on it but it broke quite badly. I'm looking for some other fun, interactive solution I could run in a kiosk mode. It being in a non-profit setting, something free or open source would be ideal, but I could maybe hunt down a budget for the right solution.

Any ideas? Seen anything out in the world that would be a fun fit?