Oddly, my favorite is an LED strip in my bathroom. It's very subtly animated, but the point is, it's red. Whenever I wake up at night, and need to go to the bathroom, I turn it on instead of the overhead light so it doesn't hurt my eyes. :)
Easily my dumbest thing by by far the most appreciated.
In the pre-Smartphone era (not really, but I didn't buy one back then), I built a printer that would output a daily report every morning that I could just take with me:
I've built a few raspberry pi based home automation systems, from relays switching my garden lights and irrigation, to 3D printed brackets and pulleys to convert my manual curtain tracks to motorised ones, WiFi controlled power sockets to switch lamps, and even a full aquarium control system managing the lighting (colour temperature and brightness), filter and aeration, and heater. I'm currently using NodeRED to build the logic and provide a web interface.
Created an automated chicken coop door which opens/closes the door based on sunlight.
It consists of:
1. Chicken coop
2. Old wiper motor to drive the door up/down (the door is suspended on fishing line)
3. Arduino Nano
4. Motor control shield
5. Light sensor
6. 2 mechanical switches for the door positions (stop the motor if switch is pressed)
7. Old car battery
8. 3 chinese 12V 15W solar panels
Maybe not something I made explicitly. But here are few things
1. A keyless lock.
2. Automatic garage door opener
3. An occupancy sensor in my work with timer of 20 minutes
4. Google home for everything else.
Easily my dumbest thing by by far the most appreciated.
https://www.flickr.com/photos/sfg/albums/72157623026358605
I used an old POS printer from eBay and an Arduino with an Ethernet shield. It was a fun thing, but was made obsolete by smartphones.
Pulled off the door handles that were broken. Gone handleless - you have to stick your hand under the gap at the bottom to open if it is too stuck.
Covered the couch in plastic liner to prevent spills.
Used a spare council collection bin as a compost heap.
*As in Tarpaulin, not a bailout. This one prevents a literal bailout.
It consists of:
Got tired of carrying laundry downstairs, so I changed one bathroom cabinet drawer into a laundry chute.