Ask HN: Project Management Suggestions (Gaming Principles preferred)

I'm looking for a new webapp to help manage my todos and enhance my planning and collaboration. There are startups for todos/PM posted all the time on HN. Unfortunately I did not keep a list and searchyc isn't all that great for generating the results I'm looking for.

I'm looking for an app that incorporates gaming principles, at the least, the ability to assign points to tasks and get instant emotional rewards when completing them.

This way I can also see the total value of tasks completed on the team.

I know somebody has built this app, and I'm pretty sure somebody has already posted it on HN. I'm looking forward to your recommendations!