I like the idea of a twitter wall. This extends it even more. The idea of Google Forms is great. At the OTA conference several of the presenters used Google Forms to get immediate feedback from the audience. It is a great tool in the classroom.
I have been thinking too about mobile devices. Many of the modern smart phones will work on wifi only. If parents/students donate old devices to the school for classroom use we could get more devices in the hands of students without a BYOD.