I am going to make a new word, "learnacrastinator", "learnicrastor" (feel free to fix/expound). One who learns a subject or skill while procrastinating studying for another.
I saw a great point in some article the other week about why Ph.d students end up doing all these incredible things in their free time - it's all an elaborate way of procrastinating from finishing their theses.
Fixing bugs in a large open-source project while I should have been studying for major exams was what landed me a Google Summer of Code position, which (I assume) is what landed me an interview at a major tech company.
Safe to say that a huge proportion of my current income is directly due to "productive procrastination" :)