Setting up a challenge blog?

I would like to set up a blog that is strictly used for digital art challenges. The blog will have multiple authors (about 5 or 6 of us) and I would like to have challenge participants be listed within either the current post challenge or maybe in a sidebar with a link to their completed challenge. I would love to not have to be able to manually enter all the names and urls.

We expect this challenge blog to get alot of traffic so I would really like to set things up correctly from day one…which is why I decided to come here and get suggestions. So is there anyone running a successful challenge blog that would like to give me some tips/pointers or plugin suggestions?

Thanks so much!

Emily