Not a musical thing per se, but it feels like it has links to 50/90 in its philosophy...
At the beginning of the year, I started a tiny fiction podcast called One Hundred Words, in which I read out a story of exactly (you guessed it) 100 words each day. It's getting close to 200 episodes now!
You can find it at https://onehundredwords.buzzsprout.com/ - most episodes are under 90 seconds long, so perfect for quick breaks between writing songs.