Just for fun, I built an app for magicians to reveal a playing card to a spectator. The spectator is asked to think of a card and then place their finger on the magician's screen - after a few seconds, their selected card magically materializes into view. So far I've been trying it on family and friends and it's been getting great reactions. Disclaimer: you probably would want to have a little bit of card trick experience for the app to be useful.
Apple: https://apps.apple.com/us/app/card-mind-reader/id1548145803
Google: https://play.google.com/store/apps/details?id=com.carddispla...