Create an accessible interface for voting on features.
Here's a simple Rails app. It has a basic login system, with 'Like' and 'Unlike' buttons for a list of features.
It should be easy to tell which feature has received the most likes. When a user places a vote, they should be able to tell that their vote has been counted.
Make sure that the interface is easy to use with a mouse, with a keyboard, and using a screenreader.