Vocational students at the Oberstufenzentrum Informations- und Medizintechnik in Berlin (https://oszimt.de) have built a 21x26 LED matrix with table tennis balls. The LEDs are controlled with an ESP32 and WLED.

Now it's up to you to do something useful with it. Programme an app to control the matrix, develop a new application for the controller or let your creativity run wild. Snake, Tetris or Pong are old favourites, but there are certainly newer ones that are worth a look.

Only constructive ideas are welcome.