Tod meets a kind of quirky girl singing off key Christmas Carols in the elevator. It turns out that he knows her, she's one of his sister's best friends.
After he calls her "nuttier than a fruitcake" they get into a discussion of fruitcakes, make a bet about fruitcake, and make a date to see each other again.
Read it to find the bet and how it all comes out. Interesting scale of female arousal, and a pretty hot sex scene. Excellent construction. Overall, a fun story.