Good free tools for running a virtual class? (Google Drive and Hangouts are not sufficient)

Folks:

Our three-day RDBMS programming class at MIT got snowed out today. We were already using Google Drive for collaboration with a shared workspace Doc into which everyone could paste a solution. So we decided to hold the class virtually using Drive and Google Hangouts.

It should have worked great. All that we had to do was tell folks via audio and in the chat window alongside the Google Doc to start working on Problem N. Then they could ask questions in the chat window or by pasting stuff into the Doc.

We ran into the following problems:

• a Google Hangout won’t allow 30 people to join as contributors; we resorted to a feature in which the teachers were in the Hangout and students could watch a broadcast version on YouTube (delayed about 20 seconds)
• a teacher with a MacBook Pro introduced a horrific echo any time that his microphone was not muted
• there was no way for us teachers to tell what the students were doing or to require each student to participate in any way
• not too many students posted questions or solutions voluntarily (shy about having the wrong answer?)

Are there any better free tools that we could have used with a little more structure? Something that would have enabled us to figure out that students were or were not paying attention? Something that would have prodded students to post progress reports? Kept track of contributions by student? Enabled anyone in a class of 25 (plus about 5 teachers) to inject some audio and video for a question? Enabled everyone to share at least one window of their screen at all times (to replace what we had available to us when we already around the classroom and could see at what stage people were with each problem)?

How does it work at University of Phoenix and similar online schools? How do the teachers know that the students are engaged?

Related: “Using Google Docs for Classroom Instruction”