Want ability for users to add poll choices

I would like the ability for registered users to add poll choices to an on-going poll, and then once a choice is added its available for all users to vote on (in addition to the previous choices available). Is there anything out there like this?

What I'm wanting to do is put out a list of 10 options and have users vote on which one is most important to them. If their option doesn't exist, I want them to be able to add it and then it be available in the list for others to vote on. Its going to be a top 10 list of things the users want to see.

Thank you!