So most people wouldn't call banging your head against an hard automation problem fun but I do. In fact I think the best way to become more productive is to have some fun with it.
I had fun tonight creating a rapid-scheduling buffer Workflow for Alfred. Although it's not perfect (or completely finished at this point) I overcame several challenges and received the awesome sense of accomplishment in the end.
Challenge yourself to solve hard problems, but have fun in the process. This is how you make your productivity "interesting".