What is your favorite way of tracking maintenance or services on your dirt bike?

I'm looking for any tips or ideas for easily tracking maintenance. Is everyone still using pen and paper or has something else come along? What's your favorite method? Is there anything you wish you could have instead?

I want to make sure to take care of my dirt bike properly so it lasts a long time. I can already see it being difficult to remember what I did and when I did it unless I record it somewhere. Also, it would be nice to have service records to show future buyers just in case I sell or upgrade.