Simple Post Voting Plugin with Daily/Weekly Voting

Hi All,
I run a non-profit competition that enables student groups to promote social action by submitting their ideas to our website and then asking friends, family, and other people to support their cause. In the past we ran the competition on a Drupal platform which was not nearly as good as WordPress but shone in one respect; voting for posts. It was relatively easy for us to implement voting on a daily/weekly basis and to allow guest users to submit posts. Now we’re having a lot of trouble finding a plugin that allows both simple functionality (Post Voting) and daily voting. Is there some plug-in that marries the two ideas?

Thanks in advance for any help offered.