How do you “warm up” before coding?

Beginning to code is usually a struggle for me, whereas continuing is easy, sometimes even addictive. Especially when I'm facing a project that's daunting and/or that I haven't looked at in a while, I find I need to coax myself into an appropriate mindset.

I've found it often helps to review the filetree, the recent history of commits, and any comments with the word "todo" in them. That feels pretty basic; I imagine there are more, and more sophisticated, methods.