Eric Mazur’s peer instruction research group has spun off LearningCatalytics.com, which uses laptops or even smart phones as glorified clickers. The range of questions it offers far surpass what ordinary clickers can do. When I tried it this semester, for instance, I could ask questions that allowed students to sketch graph shapes or even draw force diagrams (although they did look a little silly). It supports a dizzying array of question types but is pretty easy to use. On questions that it can’t immediately grade as right or wrong, it provides a good summary of student responses. I felt that it complemented Modeling well and allowed me to get at thorny misconceptions, such as those associated with Newton’s 3rd Law.
Summary:
LearningCatalytics.com
Pros: many question types, built-in functionality to form pairs of students for peer instruction, can provide direct feedback to students, allows instructors to tag and share questions and to clone and edit questions created by others
Cons: requires laptops (cost and distraction factors), yearly license cost
Ordinary Clickers
Pros: one-time cost
Cons: limited question types
Fock Physics 