1. Learn something new from a child or teenager, especially in your area of greatest expertise. I find the perspective of innocent novices to be most refreshing and enlightening.
2. Revisit an old science book you read growing up and see how your (and society's) perspective on things have changed.
3. Find someone you've always admired and tried to emulate, and thank them for being such an excellent role model, and ask them about some good stories about the "way things used to be done".
4. Find an important social topic and dig as deep as you can; follow up and look for citations, references, and raw data. For example, I learned that some theorists dispute the carbon-reduction ability of certain hydroelectric technologies, because the dams flood large regions causing them to decay, releasing methane (20x more potent greenhouse gas than CO2) into the atmosphere. Global warming appears to be a very richly textured topic with lots of unintended consequences just being realized. Unfortunately, a lot of important issues are summarized with a few "talking points" by the press and political groups. As technologists, I think we have the responsibility to always question our assumptions, and to listen to both sides of the story, and to make sure that we are moving deliberately and cautiously as a society.
5. Learn a new tool. Maybe that means picking up a new programming language, or perhaps it means learning how to use a new kind of CAD software. Or maybe it means learning a new kind of calculus or statistics, or perhaps getting into the shop and using the mill you always meant to use. Putting aside your well-worn and efficient tools is often hard to do, but it's also hard to grow when your tools limit your abilities. My new tools for the year are Solidworks and a laser cutter--I have little mechanical engineering background, and I'm hoping that learning tools like these will expand my understanding of the world and my capabilities.