March's challenge will take us to one of the most discussed diversity categories of recent times: sexual orientation. Go out and read something in the LGBT range, something about and by someone who is different than you. I am going to ask a favour of people posting recommendations here: no erotica please.
I'm not well-versed in this area, so I can't give a lot of recommendations myself. For fiction there is Nicola Griffiths, whose Hild I recently reviewed. Charles M. Blow's recent memoir, Fire Shut Up in my Bones, would be an excellent choice. I also considering Andrew Hodges' biography Alan Turing: The Enigma.
Edited to Add: The New York Public Library published a list of selections that are neither erotica nor coming-out stories. (Have they been following my blog?) And Jo Walton is right at the top! I read the first couple of chapters of My Real Children and found it very promising.
And if you just discovered this reading challenge, there is nothing at all stopping you from working through at your own pace.