This story doesn't really follow the "costume" theme, but honestly? Who cares. If you want to write a fic that deviates from that theme, I'll post it anyway.
Really? Oooh! *laughs wickedly*
This was just... OMG. completely, absolutely amazing and wonderful and... awwww!!!
My jaw dropped to the keyboard a few times throughout -- did you hear it? My coworkers did!
I'm blown away.

And I'm pretty sure I know who wrote this, too.