Funnily enough, I learned C when I was supposed to be studying for the baccalauréat. I'd learned programming in BASIC for a casio calculator(mainly for making games and a few solvers for things that we were supposed to solve manually in exams but that were too tedious). A friend of mine linked me to http://siteduzero.com/ (apparently it's changed to http://fr.openclassrooms.com/ recently) and I ended up not studying. That really hurt me in History, Geography and Biology(which require a lot of memorization) but otherwise I breezed through everything else.
PS: I'm not in France but in a country where the french baccalauréat is considered equivalent to the state-mandated exams(Lebanon, used to be under French mandate).
The word, not the fact you've just described my life.
Safe to say that a huge proportion of my current income is directly due to "productive procrastination" :)
I hadn't been doing so hot in high school (writing assembly for my TI-83's z80 was more fun than reading Shakespeare and doing derivatives), so my parents locked my laptop in the attic for me to focus on revising during that week.
Of course, I spent a few hours reading at the local library on lock picking, and managed to get my laptop from the attic on the first day (the lock was a fairly old model too, which helps). I spent the rest of the revision week writing C and hanging out in IRC :')
For the record, I did pretty well on the baccalauréat :)