Ok, so this may be old hat to some of you early adopters out there, but Kahoot has added such a fun element to my classroom. It is an educational version of adult pub trivia. The students are asked a question--and need to answer that question in a hurry. The faster they answer, the more points they get, but to get any points, the answer must be correct. My students love it so much, they even chose Kahoot for a class party.
One great thing about Kahoot, is that there are zillions already made by other amazing educators. For example, my district uses Wonders as their reading adoption. Some amazing teachers have every grade level's weekly vocabulary already created. Done and done. But, it is also super easy to make your own.
My favorite way to use it is in Team Mode. I have the students work in pairs. I love that it gives them time to chat before they answer. And then, they have someone to high five. Just be prepared, your classroom is going to become a noisy excited place!