The sample Consumer app I’ve been posting about is now running in the cloud on Azure, http://consumer.azurewebsites.net/.
The data will get wiped out from time to time, but not too often I think. Anyone can register themselves. You must give yourself the teacher role (see your profile) to create or edit assignments, but both students and teachers can launch assignments. If you select a state, district or school, you can limit the scope of your assignments to other users in the same state, district or school. You can also make them private (the default) and public (all users can see them).
Let me know if you have any questions here in the comments or at http://ltisamples.codeplex.com.