Blocking the Unblockable Curse.
This is mostly related to canon, but also a bit to HPMoR.
I've always wondered why the killing curse counts as "unblockable". In "Order of the Phoenix", Dumbledore blocks it by moving a statue in its path. Seems to work nicely. There is other evidence that solids stop the killing curse -- if it went through it, you could accidentally kill somebody behind a wall when missing your target. Prof. Moody would surely have mentioned that danger when talking about the killing curse, if that was the case. So you could carry around a steel plate strong enough to block the curse, and quickly move it into its path. Not easy, but possible.
There are also several instances where simple spells conjure animals (I remember bats and small birds). I wonder if you could simply conjure an animal into the way of the killing curse. It might need to have a minimal size to work, but a powerful wizards should be able to do that.
I also wonder if there are ways to combine charms: one detection charm that triggers another one. For example one that detects killing curses, and enables apparation or a portkey.
So, one proven way to block a killing curse, one conjectural, and another conjectural way to escape it. I can't believe the wizards still call it "unblockable" :-)
I'm pretty sure that 'unblockable' is meant to mean it was the only magic known to have no counter-effect, or counter-spell. Now Harry has discovered the true Patronus charm is the counter spell to Avada Kedavra. It makes sense when you think about it, which I'm sure is why Eliezer included it in the first place. The Dementors are voids of nothingness, into such nothingness tumble all living things once their life is extinguished (according to present evidence, anyway); in other words, the Dementors are parts of Death, but are not Death Incarnate (which...
(The HPMOR discussion thread after this one is here.)
The previous thread is over the 500-comment threshold, so let's start a new Harry Potter and the Methods of Rationality discussion thread. This is the place to discuss Eliezer Yudkowsky's Harry Potter fanfic and anything related to it. The latest chapter as of 09/09/2011 is Ch. 77.
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: one, two, three, four, five, six, seven, eight. The fanfiction.net author page is the central location for information about updates and links to HPMOR-related goodies, and AdeleneDawner has kept an archive of Author's Notes.
As a reminder, it's often useful to start your comment by indicating which chapter you are commenting on.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: