In Kahoots
I tried Kahoot today in my Geometry class. It was my first attempt and it went well. I used a public Kahoot that met my topic perfectly and the kids loved it. I’m working on one for my Calculus class to review for our test. The main concern I have is the setup time to create a good Kahoot quiz can be long. Typing in the math in the solutions is a pain. I don’t want to say much more until I’ve got more experience.
To Accumulate a Rate --- Integrate! 
My students and I love kahoot! 95 percent of the time I can find a public kahoot on the topic I am looking for, but you are right, making one can be time consuming. You could have a student make it for you.
My children love to play kahoot at home. We play with the grandparents. My dad, a doctor, actually made one for his office to play.
I thought about having students make them. That’s a great idea. The kids at home… That could be fun. Maybe for a trivia night?