We had three submissions for this challenge and the really interesting thing was the different approaches they took. One app was built on Heroku, one on Google App Engine and the other was straight HTML.
Plmcgrn finishes first and takes home the $1000 top prize! His leaderboard app was written on Google App Engine and you can run it here. Notice that you can switch the view of the leaderboard for different time periods.
Acorv finishes second with his Heroku version and takes home $600. You can run his app here.
And finally, third place, and $400, goes to xavieremerson with his HTML widget version. You can run his version here.
We will be posting the app in Facebook shortly so stay tuned for details on how to add it.