If the person is into tech, something like these Kano kits. I absolutely love them. Perfect for any age. Source: over 1 year ago

The Windows CLI is unfriendly to developers, a bit of shoving great-grandpa in the corner (despite its origins in DOS); as such, CLI developers tend not to spend much time investing in Windows-native TUI applications. With WSL, you at least mitigate a lot of that, opening you (OP) to the *nix world of CLI/TUI applications. Within WSL, you (OP) might also investigate calcurse which allows you to associate items... Source: about 1 year ago

Calcurse: fairly complex with events, reminders, notes/todos, as well as the ability to import/export .ics iCal files, customizable layout choices, etc. Source: over 1 year ago

I use evolution the gnome email client. There is also calcurse, which is a ncurses based calendar with "experimental CalDAV support", I havent used it for too long, as I need an email application anyways and it's alright. Source: almost 2 years ago

Most folks are used to a pretty visual calendar like Google Calendar or calcurse with wizards for creating events, so entering them in a text-file feels archaic/baroque. But using remind gives me a LOT more power for creating events that do weird things like having my entries modify their text based on presentation or calculations (e.g. Birthday events that say "Joe turns 31 in 7 days", adjusting the age each year... Source: almost 2 years ago

Calcurse a text-based calendar and scheduling application. Source: almost 2 years ago