I'm wondering if we could could have competitive Challenges, where one Challenge would have a face-off with another - maybe to see which one could get more books read by a certain time, or how many people could fully finish a challenge by a certain time. The reward would be bragging rights (badges? I'm not sure of that actually), and electronic confetti on the homepage for a week.

Not sure if humans should pick the faceoff partner or if it should be auto generated for a certain class of Challenge. We want to minimize the bias humans have towards meanness that the internet brings out sometimes.

Maybe there would only be one face-off per month, and people could join it or not, and choose the side they wanted to support. It could be a featured part of the community page.

There would have to be an option for Challenges to be non-competitive, as not everyone would be interested.