Most people that I've talked to and heard from about their one-*activity*-a-day project say it's an impossible challenge and after my own (failed) attempt I have to say I completely, here it comes, disagree. Not because I fared any better but because it made me realize that, stupidly, I was picking an activity that I do every single day anyways.
There hasn't been a day where in some way or another I haven't created or worked on sound or music for either my own library or projects I work on and it became harder and harder to jump out of that work to create "yet another sound" without context.
It's not hard to just hold up a field recorder to anything that makes sound but it's also not very fulfilling. So over time I decided I would stop forcing something that didn't give me anything back.
I did learn a few things, mostly that rushing something is never a good idea. Working under pressure is one thing and I don't mind that but working without context and goal is kind of pointless. So with that in mind I decided that instead of going for a "one activity a day" kind of year long project I'd rather set myself some goals on a weekly, sometimes monthly basis for creating, working or experiencing something that I don't already do anyways.
So far that has led me to go on weekly, long hikes with my wife exploring the Eifel region (and of course recording sounds and taking photos on those trips ...), I've picked up some heavy maths books from university again about problems I never fully understood but was intrigued by and finally solved / understood them, as well as many other things and guess what, most if not all of those things also gave me an opportunity to record and create really weird and amazing sounds.
So with this I can only do one last thing and highly recommend you pick a one thing a day project for yourself but just don't expect to last for a whole year, but expect to learn something unexpected!