I may get a Starbucks across the street, do my emails. I usually try to execute on 3 or 4 projects at a time. It's a common thing mathematicians do, since your brain keeps working 'in the background'.
Considering most of my projects are technology - you'll see my with either Visual Studio, XCode, or Atom open.
I try to do my work as agile as possible, so I deploy things frequently while trying not to break anything. :)