Just tell her you're taking notes for a JFC discussion, she'll probably love that.
"Honey, I'm sacrificing my sleep tonight so that I can watch the guys who are not good enough to play for the Jazz play some guys who the Jazz might be able to draft if they are really bad this year. It's important so that I can discuss what happens with strangers on the internet. Also, there's no way I can get to the dishes tonight, I'm way too busy. "