What methods do you use to keep track of your todos and check the progress on a regular basis?

From Wikipedia: In business, education, and psychology, self-management refers to methods, skills, and strategies by which individuals can effectively direct their own activities toward the achievement of objectives, and includes goal setting, planning, scheduling, task tracking, self-evaluation, self-intervention, self-development.

http://en.wikipedia.org/wiki/Self-help

What are your favorite tools? Todo lists on a piece of paper? Your computer, PDA or cell phone? Your refrigerator? Your memory in your brain? What does really work for you and what doesn’t?