I just want to list a few ideas of challenges that I could get running:
- 365 days writing challenge
- 365 days anti-procrastination challenge
- 365 days twitter challenge
- 365 days design challenge
- 365 days coding challenge
Those obviously need some marketing rework (this could also be a challenge, the 365 days marketing challenge), but there are quite a lot to do with that.
Also, 365 days may not make sense in some cases. They could be shorter if the goal is to learn something.
If the goal is to create a specific behavior, 365 days would probably be the best.
If the goal is to learn the basics of a topic, getting to 20 hours of practice would be a great goal. With 20 minutes a day (which can already be hard to get to), that would make it a 60 days challenge.
I will start with the anti-procrastination challenge. It will go from very small tasks taking a few seconds to larger ones in the end that could take hours. There will be safety hatches not to lose momentum, but the goal is to be able to work on something specific in hard conditions for 1 hour everyday.