A colleague of mine used a tool call Padlet in a classroom setting during a presentation to foster open collaboration with attendees. Padlet is a collaborative website which allows posting small tidbits of information in a series of “wall-like” pages. A bit like a community board filles with sticky notes of links, videos and the like.
If you fiddle with the access settings of a padlet site, you can create a semi-open collaborative activity with a class.
Here is a quick tutorial I found on Youtube:
In fact, this tool reminds me of this interesting list of iPad apps presented at this training event in my university:
Paid Apps (optional)
Greenscreen by DoInk
This list is an interesting starting point to explore new tools that can engage learners in a new way.