I can't really do it justice, so I'll just link Dave Thomas's LJ post, and you can follow his link. Wow. I don't even know how to describe my reaction to this -- I guess it's one-half "Cool!", one-half "Ewwww!", and one-half "Huh?!" Yeah, I know that's three halves. That's part of the problem.
UPDATE: It's brought to my attention, by a blogger I respect, that I have perhaps wandered into a bit of mean-spiritedness here, and looking things over, I have to plead, mea culpa. Part of it is that I genuinely don't know what "cosplay" is, and therefore greatly misinterpreted what was going on here. I had assumed something, well, sexual in nature; it turns out that's not really it. (Turns out that "cosplay" is sort of like when people go to Renaissance Faires dressed up in costume, but instead they dress as anime characters.) But that's not really an excuse. I do try, as a general rule, to avoid mean-spirited mocking; unfortunately, like everyone, my efforts aren't always successful.
I'm leaving the original post above, since I don't believe in redacting my mistakes and deleting posts as if they never happened (it's always bugged me how members of the US Congress can have stupid things they say stricken from the Congressional Record), but apologies around -- especially to the young woman whose picture I obliquely reference above.