Using a CRS (Classroom response system; aka Activote) is one way I use technology in the classroom. Everyone participates; the shy and the extroverted all have the same voice; I can see wherein lies difficulty and address it. An instant graph can be displayed for each response to show how many students got the question correct. This is good both as a pre- and a post- test. In math class, it can be used a quick check to see if a key concept is understood.
CRS can also be used to vote. For example, I read aloud a "Choose your own path" type of book, and at each decision point, we used the voters. Majority determined the path the hero of the book would follow. The kids really enjoyed this interactive read!