My favorite technology that has been implemented would definitely be answering clicker systems. I like that you can get response in real time, I even had a class that took quizzes using the clickers at the end of classes.
I am currently in college and taking an educational technology course. We had a guest speaker a few weeks ago that shared some technology she is using in her classroom. She was using a classroom set of clickers. I thought it was very neat because it helped with grading, looking at what questions are missed most, and it helps the students take quizzes in a new way.