At the end of this, there's a prize!

Edit: The correct answer does appear in the comments. I'm going to announce who won at some point today, and start putting a Miss Grace Care Package together thusly.

(click to embiggen)

The person not related to my by blood or marriage to accurately guess wtf my sister and I are talking about gets a care package prize!  If there are more than one of you I will come up with a clever way to select, such as random.org, or maybe I'll choose with glitter!  Tell your friends!