1/ Installed a flavor of Debian Linux on an elderly, failing MacBook Pro (2010). Was fun and I was slightly surprised how fast a 2020 distribution runs on a 10 years' old hardware. Unfortunately it seems there's actually a hardware failure (I suspect the voltage on the power rail) so the next step is picking it apart, taking aside the SSD, RAM, HDD and the newish battery to transplant them into a slightly newer MacBookPro (2011) before final retirement.

2/ Had the mobo replaced on a 2017 Macbook Air - under warranty, so it's not very "techy"

3/ Had first contact with Android, in the form of our new TV set. Upgraded the OS and spent some time going through all menus to deny phone-home wherever possible.