Check out the following websites for ideas on creating your own Rube Goldberg Machine. 

Teach Engineering - https://www.teachengineering.org/makerchallenges/view/lau-2321-simple-machines-mechanisms-rube-goldberg-challenge

Tinker Lab - https://tinkerlab.com/engineering-kids-rube-goldberg-machine/

How to Make a Rube Goldberg Machine - https://boyslife.org/hobbies-projects/projects/159359/how-to-make-a-rube-goldberg-machine/

Connections Academy - https://www.connectionsacademy.com/support/resources/article/build-your-own-rube-goldberg-machine

Dog Feeder Example - https://youtu.be/OHwDf8njVfo