Looking for a cheap dopamine hit ;)

I love playing with my HA and associated devices. I suspect that most of you reading this get a bit of a jolt every time you add and incorporate a new sensor, camera, integration and get to play with it.

I have all the door/window sensors and locks/covers, every angle of my exterior covered with cameras, alarm, network devices, appliances, sprinklers, household devices covered.

Any ideas for a new thing I can play with?