We talked about all of the black characters in Harry Potter e.g. Dean Thomas and the racial transformation of Lavender Brown from black to white once she became Ron's love interest (in the movie). We also talked about the characters that are racially ambiguous in the book e.g. Hermione Granger. It was never something that we'd recognized fully as children, but the ambiguity surrounding her race became readily apparent upon really parsing it out.
A Buzzfeed community member created a post about a "racebent" Hermione Granger, and it is all kinds of amazing awesomesauce. Check out a few images of a "racebent" Hermione Granger in the slideshow below and then read the post in its entirety at Buzzfeed.