Like Kahoot, Socrative is way to get questions to students who can answer with their smart devices. You can develop open ended questions, multiple choice questions, true false questions, or short answer questions.
Answers come immediately and you can project them because student names are not attached. Students can even "vote" on their favorite responses.
There are lots of applications across disciplines. I want to try it in my AP World History classes with thesis writing. After we review how to write a thesis, I could give them a prompt and ask them to respond on Socrative. I could then project and review the responses and have students then "vote" on their favorite.
Here's a clip explaining how to get started with Socrative.