I use KeePass and Syncthing, but for mild fun I like Lexica and StreetComplete.

Lexica is a word finding game on a grid with a timer, and it’s very customizable (size of grid, min length of words, length of timer, etc). Words can and often do cross over themselves and run in all directions. Invariably I will miss stupid obvious words, and I’m always interested to see the list of missed words at the end. They provide definitions for the ones you just don’t believe and have to click.

StreetComplete is a way to update Open Streetmap with goals and badges and all that gamification jazz. For an additional personal challenge, try updating house data without making homeowners look at you funny and/or call the cops.

Oh yeah, I use IITC-CE too, because Ingress is life. And Niantic can take a flying leap.