Teachers in US universities are allowing students to answer multiple-choice questions with wireless keypads.
The devices sends infrared signals to a receiver connected to a computer, which tabulates and analyzes the responses. The data can be displayed by an overhead projector, incorporated into a spreadsheet or posted on a class Web site. Responses are anonymous among the students, but the teacher can identify students by the serial numbers of their clickers.
The benefits are that students participate more than before, while teachers can gauge whether he/she is getting understood and adjust lectures accordingly.
Read more in New York Times