Our requirements were what you might expect with an advanced search functions. We wanted users to be able to easily search for any combinations of open/closed challenges, by category or keyword and sort them by criteria such as challenge name, start date, end date and category name.
Peakpado was our winner and not only did you win $1000 but since it was his first CloudSpokes win, we doubled the prize money! Congrats!
His app is hosted on Heroku so you can run it here for yourself. Here's a quick rundown on its features.