I was or am watching A Mom for Christmas with Olivia Newton-John and this idea popped in my head. Of course Ginny couldn't be a mannequin though.
Challenge:
1. Draco has a child (girl or boy--the mother is either dead or left--doesn't have to be a relationship where they both loved each other)
2. The child some way or another says he/she wants a mom for the holidays which Draco happens to over hear. (Draco loves his son or daughter)
3. There's an ad and Ginny decides to do it.
Where you go from there is fine! I'd prefer them to still dislike each other for a bit and to slowly ease in to the whole liking thing.
Bonus Points: If Draco figures out he's in love with Ginny first. I know it's kind of a cheesy challenge, but it'd be cute!