What are some alternatives?
When comparing Tweek.so and Teuxdeux, you can also consider the following products
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
Google Calendar - Spend less time managing your day & more time enjoying it
Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.