I'll tell you guys what: Because, as John Steinbeck said:

"Ideas are like rabbits. You get a couple and learn how to handle them, and pretty soon you have a dozen."

And because, unlike tangible stuff, my collection of stories-waiting-to-hatch is not definite (I'd hope they were infinite, but one never knows...), I will write a story for every person who bids on my item in the auction.

The highest bidder will get their story written first, of course. The second highest bidder will get their story written second, the third highest bidder, third ... and so on...

Let's see if that doesn't bring out the Grandparents!