Students can use Twitter to create a “back channel” of comments and questions during a lecture, a potentially rich source of immediate feedback.
Students can create their own videos on class content—not just as final projects, but as exploratory pieces—and provide feedback to one another using standard tools like YouTube.
Students can create “mashups” that combine data from multiple sources to analyze and visualize disparate data. The most common examples involve overlaying content onto maps—say, the locations of local social service agencies versus local bus routes clients may need to reach them.
Students can use wikis to create their own collaborative notes and study guides, using group participation to correct and enhance the guide as it grows from the students themselves.
Similarly, you can “crowdsource” exams by asking students to generate potential questions, refining them through a tool like a wiki.