On a related note, is it okay to pick up skills related to your side project at work? For example, if my side project is building a application in Clojure, is it okay to learn about Clojure at work? Of course, not at the expense of getting actual work work done, but there's always time between builds, etc. So instead of playing Foosball or surfing the internet, can one actually do something more productive, even though it's unrelated to the current work you are doing?