So while I see the simplifying assumption that says "I could do that in one weekend" and that it's really not that simple. There's the other side of the coin. Maybe some ideas don't need to be so complicated. We evolved our game idea three times that weekend as we completed something we saw what was boring or was failing and modified it.
In both our case and the guy above, we aren't planning to continue the game. I know I tend to sit and idle on ideas for months or years at a time. This is a terrible thing to do. Why not, for the cost of one weekend decide to throw it in the trash and never think of it again. One weekend is way less than months and months of planning and task lists and bug trackers and code repositories... etc etc.
Edit: In case anyone is interested you can find our game on http://globalgamejam.com called "Maid of Dishonor" or on our site, http://tosos.com under the "Unity Games" page.