If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
:-)
It's not particularly hard to "perfect" your calibration in that game -- if you're over/under on a certain percentile, you can throw questions where you're confident into percentiles where you're "poorly calibrated" in order to spoof a good calibration curve.
The trick to that game, if you actually want to asses your calibration, is to play for points rather than for a good curve. Being well-calibrated means that when you play for points, you have a good curve automatically.
(I wish that they'd show you your curve less often, perhaps only when you leave the game. It's hard to resist cheating the curve. Then again, I'm not sure of a better way to provide the necessary feedback.)
I'm not strong enough in math to figure out how the scoring actually works without spending some time with it, and I wouldn't "throw" questions anyway. But I do like seeing that, say, on my 60%s I'm actually right 70% of the time. So when I'm feeling "60%" I should actually go with 70% more often. I think I'm afraid of getting questions wrong because the score penalty appears so high relative to the score bonus (I know that's likely appropriate, even though I don't understand the actual log bits, etc of scoring ).