The 100 Day Project is a creative challenge that invites participants to choose some kind of action and repeat it daily for 100 consecutive days. I attempt this project every year and it has been one of the most valuable things I've ever done for myself and my creative practice!
Traditionally, the goal of the challenge isn't to churn out time-intensive fantastic final results*; rather, the daily task should be small — "the warm-up before your real work begins" — in order to allow the participant to meditate on and learn from small deviations in their process. Initially created as a grad school workshop by designer Michael Beirut, the concept found a community on Instagram starting in 2015 (thanks to artist Elle Luna) and now repeats every year with a huge global cohort of creators. (For more info, see the100dayproject.org.)
* Admittedly, I don't always take this advice and have certainly suffered because of it. Sometimes that suffering is worth it, sometimes it's not. I recommend starting very small and certainly not with a 2–3+ hour daily sewing commitment.