You are describing IPFS. If you install IPFS, then browse to some IPFS content (like a wikipedia mirror: ipns://en.wikipedia-on-ipfs.org/wiki/), that’s cached on your system, if someone else requests those assets, your computer will help distribute it. You can “pin” content, keeping/seeding a copy.
Garage sensor. Uses distance sensors to detect door open/closed and car present /absent. Has buttons to open/close the doors, a 3v garage door remote. Also has a motion sensor, temp/humidity sensor and a photo resistor to understand outside ambient brightness.
Looking at building some fridge/freezer temperature and water leak sensors.